Amid the dynamics of contemporary economic challenges and the increasingly urgent need for financing within the Islamic finance sector, Islamic law is confronted with a range of issues that demand careful consideration, particularly those related to the development of Islamic economic law ((Bhuiyan et al., 2020); (Radzali et al., 2019); (Windiastuti & Athief, 2019)). In this context, the objectives of Islamic law (Maqashid al-Shari'ah) and the methods of legal determination (fiqh) must be reformulated in ways that are contextually relevant. Scholars are expected to offer practical and principled solutions to the legal and economic issues faced by society, particularly in the field of Islamic finance. They hold a key role in guiding the community toward realizing the broader aim of achieving well-being and prosperity in both this world and the hereafter.

Indonesia as the country with the largest Muslim population in the world places considerable importance on the role of ulama in shaping socio-religious life. One of the most significant contributions of the ulama is the issuance of fatwas which serve not only as religious guidance but also as a foundation for institutional development, including the growth of Islamic financial institutions (Fauzi, 2017). The recent and rapid expansion of Islamic financial institutions in Indonesia has increased the demand for legal clarity and uniformity in financial practices. This situation highlights the critical role of the Sharia Supervisory Board (Dewan Pengawas Syariah or DPS) in each institution, which functions under the oversight of the National Sharia Board -Indonesian Ulama Council (Dewan Syariah Nasional -Majelis Ulama Indonesia or DSN-MUI) (Dakhoir, 2019).

In Islamic law, fatwas play a vital role as responses to emerging societal issues. They are issued by scholars or muftis, either individually or collectively, in response to specific legal questions. Although fatwas are generally non-binding (ghairu mulzimah), they carry significant religious authority and practical influence, especially in areas where explicit rulings from the Qur'an or Sunnah are not available (Achmad et al., 2022). In economic matters where legal complexity often exceeds the scope of classical texts, fatwas provide much-needed interpretive guidance.

The DSN-MUI is tasked with formulating fatwas that govern Islamic financial transactions. It is composed of scholars of fiqh and practitioners of Islamic banking who are entrusted with ensuring that economic activities comply with Sharia principles. In addition to issuing fatwas, the DSN-MUI monitors their implementation through the DPS at the institutional level (Asri et al., 2020). According to (Amin, 2011), the DSN-MUI follows a systematic and procedural approach to fatwa development, thereby enhancing its legal coherence and effectiveness.

One such method is istihsan bi al-'urf, a form of ijtihad that prioritizes customary practices when they align with public interest and Sharia objectives (Khallaf, 1972). This method is especially relevant in cases where traditional sources such as the Qur'an, Sunnah, ijma', and qiyas do not offer specific rulings. Reconsidering istihsan bi al-'urf within the context of Islamic finance may enhance the legal adaptability required to address contemporary economic needs.

This study examines the use of istihsan bi al-'urf in DSN-MUI fatwas issued between 2010 and 2018. By applying a normative legal research approach, it aims to assess how this method of reasoning has been employed in addressing financing issues in modern Islamic economic transactions. The analysis focuses on identifying whether and how istihsan bi al-'urf contributes to the development of fatwas that are both contextually relevant and consistent with Sharia principles.

In the context of Islamic banking and Islamic economic practices, various financial transactions often arise that have not been explicitly addressed by earlier legal rulings. In Indonesia, Islamic banking and economic activities are legally governed by fatwas issued by DSN-MUI as an institution established and supervised by the MUI (Amin, 2011). The continual development of Islamic economic law is essential to keep pace with a dynamically evolving economic environment, thereby ensuring that legal interpretations remain a valid reference (hujjatul Islam) in practice ((Ikhsana & Khasanah, 2020); (Kasdi, 2018)).

Sharia economic law continues to evolve, but the number of core legal texts remains limited and finite. In such cases, the role of mujtahids becomes crucial, as they are expected to issue fatwas in response to newly emerging issues in Islamic finance and economics. These fatwas must be based on ijtihad, as leaving individuals to interpret legal rulings on their own in such complex matters could lead to inconsistencies and legal uncertainty (Amin, 2008). The DSN-MUI is the sole institution in Indonesia authorized to issue fatwas concerning Islamic banking products. Given the collective obligation (fardhu kifayah) attached to issuing correct legal guidance, mistakes in this process must be carefully avoided. Consequently, DSN-MUI employs a range of istinbath al-ahkam methods, including qiyas, istihsan, ‘urf, istishab, maslahah mursalah, and syar‘u man qablana to derive legal rulings appropriate to contemporary contexts (Izmuddin, 2018).

A fatwa must always be grounded in established legal sources. Issuing a fatwa without such a foundation is considered an arbitrary act (tahakkum), which is not permissible in Islamic jurisprudence. Legal arguments (adillah al-ahkam) include verses from the Qur'an, hadith, scholarly consensus (ijma'), and established fiqh principles. In practice, DSN-MUI also considers the opinions of classical and contemporary scholars as well as rational arguments ('aqli) in determining the legal basis of a fatwa (Mundzir, 2021).

Before issuing a fatwa, DSN-MUI thoroughly examines classical legal arguments and jurisprudential opinions. If the issue at hand has an unambiguous ruling (al-ahkam alqath'iyyat), the fatwa follows that position. However, if there is scholarly disagreement, DSN-MUI attempts reconciliation through al-jam'u wa al-tawfiq. If reconciliation fails, the fatwa is based on tarjih (preference of stronger evidence) through muqaranah al-madhahib (comparative jurisprudence) using the principles of usul al-fiqh al-muqarin. When no clear answer is found in existing schools of thought, the fatwa is determined through ijtihad jama'i (collective ijtihad) employing methods such as bayani, ta'lili (including qiyasi, istihsani, ilhaqi), and zari'ah. In all cases, the fatwa must reflect public benefit (maslahah 'ammah) and uphold the objectives of Islamic law (maqashid al-shari'ah) (Mubarok & Hasanudin, 2017)(Mundzir, 2021).

Previous studies have demonstrated the relevance of classical legal methods like 'urf, istihsān, and maṣlaḥah in modern Islamic legal development, but with limited focus on fatwa practice. (Athief, 2019) found 'urf to be contextually influential in shaping legal norms, yet his work did not examine its use in formal fatwa texts. (Muslimin & Kharis, 2020) highlighted the applicability of istihsān and istishḥāb in resolving contemporary legal issues, but without tracing their institutional use. (Ishak & Sharoni, 2022) affirmed istihsān's role in Islamic finance to balance Sharia and modern business norms, though their study remained conceptual. (Mujahidin, 2022) showed that maṣlaḥah guides DSN-MUI's fatwas, but did not explore specific ijtihād tools employed. (Ismail et al., 2022) revealed 'urf's contribution to inheritance reform, while (Darliana et al., 2022) confirmed istihsān's value in legal renewal, yet neither addressed its operationalization in fatwa issuance. Thus, while prior works explore the relevance of ‘urf or istihsān in theory or in isolated sectors, this research is the first to document their combined application (istihsān bi al-‘urf) in authoritative fatwa texts over a systematic period.

This study adopts a normative-juridical approach to examine the application of istihsan bi al-'urf as a method of Islamic legal reasoning in fatwas issued by DSN-MUI. This approach is appropriate for analyzing legal norms and texts to understand how Islamic law is interpreted and applied in formal decisions (Adam et al., 2022)(Rosyadi et al., 2022)(Soekanto, 2007). The research focuses on 49 DSN-MUI fatwas issued between 2010 and 2018, a period selected to examine contemporary fatwa developments in response to increasingly complex Sharia-compliant financial products in Indonesia. These fatwas serve as the primary legal material. The objective is to determine whether istihsan bi al-'urf, which allows customary practice ('urf) to serve as a basis for legal rulings in the absence of direct textual evidence, was used explicitly within the fatwas' legal reasoning. To explore this, the study employs a document analysis technique, a method commonly used in qualitative legal research to examine the content, structure, and sources within official legal documents (Bowen, 2009)(Salleh et al., 2021)(Wan et al., 2019).

From this review, only one fatwa, Fatwa No. 119/DSN-MUI/II/2018 on ultra-micro financing, was found to explicitly apply 'urf as a component of its legal justification. This fatwa was selected for in-depth analysis to assess how istihsan bi al-'urf is integrated into DSN-MUI's interpretive framework. The analysis was supported by secondary legal materials, including classical works of usul fiqh, books on Islamic jurisprudence and fatwa methodology, and contemporary academic literature discussing the application of Islamic law in modern finance. These sources were used to contextualize the concept of istihsan, clarify its types (including istihsan bi al-'urf), and explain its role within the broader framework of ijtihad. In addition, tertiary materials such as legal dictionaries and glossaries were consulted to ensure accurate interpretation of technical terms and institutional references.

Financing products are constantly evolving to meet the consumptive and productive needs of society. These developments require continuous ijtihād by Islamic scholars to ensure that emerging financial models remain compliant with Sharia and free from elements of riba. In response to rapid changes in the global economy, Islamic financial products have become increasingly dynamic while often mirroring its conventional counterpart. Consequently, Islamic financial institutions are compelled to engage with these evolving forms while maintaining their religious integrity. This pressure places responsibility on DSN-MUI to issue fatwas that both preserve Sharia principles and respond to the practical needs of the community. As (Susanto, 2015) notes, this reality demands active ijtihād, particularly as fatwas evolve from simple, single-contract models to more complex structures. In this context, fatwa scholars must carefully consider the legal foundations of economic transactions to avoid riba and to ensure that their rulings provide maṣlaḥah for both the public and Islamic financial institutions (Abdulahanaa, 2014).

One example of such adaptive legal reasoning is found in Fatwa No. 119/DSN-MUI/II/2018 on ultra-micro financing. This fatwa addresses financing arrangements involving multi-item or multi-service purchases where the quantities or values are not fully determined at the time of contract. The final price is estimated in advance based on the buyer's projected needs and paid at a fixed amount, including a profit margin. While this structure deviates from traditional contract rules that require clarity in quantity and price, DSN-MUI permitted it by referring to prevailing customary practices ('urf) as part of the legal justification. This use of 'urf aligns with the method of istihsān bi al-'urf, which allows deviation from general rules in favor of contextual benefit grounded in custom. Notably, this fatwa is the only one among 49 DSN-MUI fatwas issued between 2010 and 2018 that explicitly applies 'urf in its legal reasoning. This finding serves as the foundation for the current study, which investigates how istihsān bi al-'urf has been operationalized within fatwa issuance and evaluates the extent of its formal use in shaping Sharia-compliant financial regulations.

Maslahah is one of the considerations of Indonesian scholars when enacting a law, including a fatwa on ultra-micro financing; this financing is financing for the purchase of various goods and services in very small amounts. Alongside the consideration of maslahah used by scholars, there are several other considerations, such as requests for fatwas by other institutions, including in determining the permissibility of ultra-micro financing.

Several provisions that must be considered in buying and selling transactions include the existence of pillars that require the existence of a seller and a buyer, goods, and prices, as well as consent and qabul. According to the number of scholars from several pillars that have been determined, there are conditions that must also be met, namely that goods and services must be halal so that transactions for goods and services that are haram are null and void, the prices of goods and services must be clear, the place of delivery must be clear, and goods transacted must be clearly fully in ownership (Hidayatullah, 2019)

In this ultra-micro financing, there is uncertainty regarding the price of the goods or services transacted because the number of goods transacted varies. However, this financing is considered legitimate by the board with some legal sources and some considerations. DSN stipulates this ultra-micro fatwa with the consideration that many people need assistance in distributing funds from Islamic financial institutions with the principle of buying and selling and/or ijarah. Additionally, this fatwa also responds to the needs of the community to carry out and improve welfare in various other economic transaction activities aimed at benefitting the people. Therefore, Islamic financial institutions have facilities for ultra-micro financing products.

The arguments used in determining this ultra-micro financing comprise quotations from the Qur'an and Hadith. In terms of the methodology of this fatwa regarding ultra-micro financing, it uses the ijma' method taken from the work of the majority of scholars regarding the permissibility of buying and selling on a murabaha basis. Alongside these methods, this fatwa also includes general fiqh rules.

Sharia provisions relating to muamalah generally also apply in contracts (Maksum, 2013). So that the permissibility of this ultra-micro financing fatwa is equipped with general rules, including al-ashlu fil muamalat al ibahah illa an yadullu dalilun 'ala tahrimiha, a very general rule became the first rule used by scholars to determine the permissibility of this fatwa. In addition to these rules, several other fiqh rules are included in the fatwa, such as the

These fiqh rules are the same as the previous ones, namely the general rules used in the stipulation of a law that has the opportunity to meet the legality needs of ultra-micro financing. The ultra-micro financing fatwa's combination of contracts is a sort of modification by DSN. Modification of the contract is an innovative approach to filling a void in law whilst also ensuring that current transactions meet their legal requirements. Fatwa scholars are typically the ones who carry out these actions because they do not originate from existing contracts (Maksum, 2013).

In the last rule, the ulama includes a general rule regarding benefit, which is the main method used to determine the permissibility of fatwas with the aim of maslahah to the community, namely the rule of aynamā wujidati al-maṣlaḥatu fa-thamma ḥukmullāh. This rule is the most important consideration in determining the ultra-micro financing fatwa (Soemitra, 2019). According to Al-Buti, maslahah is a benefit or enjoyment for humans based on the five universal principles of Islam, with the formulation of maslahah boundaries that are in line with Islamic Sharia. Maslahah is used in legal considerations to achieve good, avoid harm, and realize legal clarity; it is in line with common sense and has implications for the interests of the people/universal dimension (Solikhudin, 2019).

If sharia and maqasid sharia are aimed at benefitting the here and the hereafter, then they must be measured at the level of basic human requirements, according to al-Syatibi. For example, the concept of fulfilling human wants, the paradigm of economic activity, and utility standards in meeting the needs for products and services are all significant in the development of sharia economics, since maslahah values can be implemented. The notion of maslahah, taken from the fiqh rules regarding maslahah, refers only to meeting utility criteria in obtaining goods and services needed by the community so that the objective of sharia, i.e. to make people prosperous, is fulfilled in the determination of the ultra-micro finance fatwa.

Besides some of the rules used in determining this fatwa, there are several considerations which fatwa scholars take on board when paying attention to the first, al-ma'ayir al-syar'iyyah AAOIFI regarding dhabit al-gharar al-mufsid lil muamalat al maliah. Second, the opinion of the scholars regarding the permissibility of the mu'allaq contract includes the opinions of the majority of Hanabilah scholars as well as the opinions of Ibn Taymiyah and Ibn Qayyimah al-Jauziyyah al-Hanbali. Third is the letter from the sharia business unit of Bank Aceh No. 683/DIR/II/2016 dated 15 February 2016 regarding the request for a fatwa opinion. Fourth is the letter from Bank BTPN Sharia No. S.205/DIR/BSPD/V/2016 dated 10 May 2016 regarding requests for opinions and DSN fatwas for the use of murabahah jizaf. Fifth is the opinion of the participants of the DSN plenary meeting on Thursday, February 22, 2018 (Sholeh, 2016).

As regards some of the legal bases and considerations, the fatwa for ultra-micro financing is determined based on sharia principles by taking into account the following general provisions: first, that ultra-micro financing is financing with a collection of various goods and/or services whose value is very small. Second is the use of contracts in ultra-micro financing using murabahah sale and purchase contracts, salam sale and purchase contracts, istishna' buying and selling contracts, and parallel istishna' buying and selling contracts.

The provisions in this fatwa are still associated with several other provisions, namely multi-goods ultra-micro financing may be carried out with a sale and purchase contract, so it must be subject to and comply with the provisions and limitations in the DSN-MUI fatwa No. 110/DSN-MUI/IX/2017 concerning buying and selling contracts. If one uses a murabahah sale and purchase contract, one must comply with the provisions and limitations contained in the DSN-MUI fatwa No. 04/DSN-MUI/IV/2000 regarding murabahah. If ones uses an istishna' and/or parallel istishna' sale and purchase contract, then one must comply with the provisions of the DSN-MUI fatwa No. 06/DSN-MUI/IV/2000 regarding istishna' buying and selling and the DSN-MUI fatwa No. 22/DSN- MUI/III/2002 concerning parallel buying and selling. If one uses a salam sale and purchase contract, one must comply with the provisions and limitations contained in the DSN_MUI fatwa No. 05/DSN-MUI/IV/2000 regarding the sale and purchase of greetings.

As for multi-service ultra-micro financing, if one uses an ijarah contract, one must comply with the provisions and limitations in the DSN-MUI fatwa No. 112/DSN-MUI/IX/2017 regarding the ijarah contract. However, if one uses the ijarah Muntahiyyah bi al-tamlik contract, one must submit and obey the DSN-MUI fatwa No. 27/DSN-MUI/III//2002 concerning al-ijarah al-muntahiyyah bi al tamlik. This financing can also use ijarah and kafalah contracts, meaning one must comply with the DSN-MUI fatwa No. 09/DSN-MUI/IV/2000 regarding ijarah financing, fatwa No. 44/DSN-MUI/VIII/2004 regarding multi-service financing, and DSN-MUI fatwa No. 11/ DSN-MUI/IV/2000 on kafalah.

Determination of the permissibility of this fatwa is also equipped with provisions for the implementation of ultra-micro financing contracts: the implementation of ultra-micro financing contracts must fulfill the pillars and conditions stipulated by the DSN-MUI fatwas; if there are difficulties in implementing the buying and selling contract and leasing contract in this fatwa, then the parties may use the main contract and wakalah contract as a complementary contract, or can use the mu'allaq contract in the main contract plus the wakalah contract as a complementary contract; in a mu'allaq contract, the object of goods or services must be clear and measurable specifications (quantity and quality) according to business habits ('urf tijari); the use of the mu'allaq contract by the customer must be effective when a representative carries out the wakalah object; and customers are required to report the implementation of the wakalah contract with relevant evidence according to 'urf no later than 15 days after the implementation (Choiriyah, 2019).

The consideration of 'urf is used by Indonesian fatwa scholars as a legal basis and is a kind of support which the community can use to form prosperous people in assessing the maslahah category without leaving other considerations so that the sharia in the multi-goods and/or multi-service ultra-micro financing fatwa is realized by considering several legal bases that must be taken into account. It should be noted that the determination made by looking at the existence of 'urf is a form of decision-making with istihsan considerations.

Indeed, the position of Istihsan as a method of taking the law (istinbath al-ahkam) is still debated amongst the Hanafi and Shafi'i jurists. Shafi'i scholars have rejected the use of Istihsan as a method of taking the law because it is not based on arguments originating from the Qur'an or Hadith. Meanwhile, Hanafi scholars use Istihsan in view of the use of stronger arguments because they are based on emergency affairs aimed at facilitating community affairs (Zahrah, 2005). The Qur'an explains that religion is not designed to complicate human life, and it has been revealed that religion provides benefits in human life. Thus, the ijtihad method through istihsan al 'urf needs to be reviewed and the purpose of the benefit considered.

As Imam al-Bazadawi, an expert in ushul fiqh from the Hanafis, defines Istihsan as meaning “turning away from a stronger will of qiyas or specialization of qiyas based on stronger arguments because according to him in certain legal cases the qiyas method is difficult to apply, because the existing illat on qiyas is very weak” (Usman, 1999). Thus, it is necessary to find another method that is stronger, so that the law applied to a particular case is more appropriate and in line with the objectives of the syara. Imam al-Syatibi explained that the Istihsan rule is the result of induction from various verses and Hadiths as a whole, which clearly shows that this rule is supported by syara. For example, in the provisions of the musyarakah mutanaqisah contract, where the contract is divided into two contracts in one transaction, by using a stronger argument for benefit, the Istihsan rule is formulated.

Hanafi scholars divide several kinds of Istihsan, which are related to the theory of maqashid al-sharia (Al-Syalabi, 1981): a. Istihsan bi al-nash (istihsan based on a verse or Hadith), that is, there is a verse or Hadith about the law of a case that is different from the provisions of general rules; b. Istihsan bi al-ijma (istihsan based on ijma'); c. Istihsan bi al-qiyas al-khafy (istihsan based on hidden qiyas); d. Istihsan bi al-maslahah (istihsan based on benefit); e. Istihsan bi al-urf (istihsan based on customary contract); f. Istihsan bi al-dharurah (Istihsan based on an emergency) refers to an emergency situation that causes a mujtahid not to apply general rules or qiyas (Mubarok & Hasanudin, 2017).

This study examined the application of istihsan bi al-‘urf as a form of Islamic legal reasoning in fatwas issued by the National Sharia Board – Indonesian Ulama Council (DSN-MUI) between 2010 and 2018. Through normative-juridical analysis of 49 fatwas related to Islamic economic transactions, the research identified that istihsan bi al-‘urf was explicitly applied in only one fatwa, namely Fatwa No. 119/DSN-MUI/II/2018 on ultra-micro financing. In this fatwa, prevailing custom (‘urf) was used to support the permissibility of financing structures that involve uncertainty in quantity and pricing.

Although istihsan bi al-‘urf appeared only once within the analyzed period, its use illustrates that DSN-MUI has the capacity to adopt context-sensitive legal reasoning in response to contemporary financial needs. The selective but deliberate inclusion of customary-based ijtihad indicates an openness to integrating traditional legal methods with practical considerations in modern Islamic finance. This study shows that DSN-MUI engages in adaptive legal reasoning that upholds the foundational values of Sharia while addressing the realities of economic transactions. Accordingly, the findings underscore the importance of further exploring and refining tools such as istihsan bi al-‘urf to enhance the responsiveness and relevance of fatwa development in the Islamic finance sector.