According to search-discovered classical Islamic scholarship, the concept of customs (العادات) is addressed with a critical and nuanced lens. The Quran, as interpreted by exegetes like Ibn Kathir, unequivocally condemns the blind imitation of ancestral customs that contradict divine revelation, a theme highlighted in verses 2:170 and 5:104. These verses critique the rejection of God's guidance in favor of the unguided practices of forefathers. However, this condemnation is not absolute. Islamic jurisprudence (fiqh) developed the sophisticated principle of 'urf (عرف), or social custom, as a secondary source of law. As jurists like al-Qurtubi explain, a custom is considered valid and authoritative only if it does not conflict with the explicit texts of the Quran and Sunnah, is widely practiced, and does not lead to corruption. This legal framework, supported by the Prophet's own actions of retaining certain pre-Islamic customs, allows Islam to remain adaptable to various cultural contexts while ensuring the supremacy of Shariah. Thus, Islam distinguishes between rejected customs ('urf al-fasid) rooted in ignorance, and accepted customs ('urf al-sahih) that are beneficial and in harmony with divine law.