Abstract
Sheikh Abu Ja'far Mohammad ibn Ya'qub ibn Isaac Razi, known as Kolayni, the most famous theologian, jurisprudent, and Shiite scholars in the first half of the 4th century AH, has been the author of many books, among which only El Kafi has survived. Al-Kafi's book is the first comprehensive Hadith and provider of an epistemic system. Kolayni has emphasized in the book sufficient reason, reason, Quran and Sunnah as the source of religious knowledge and the relationship between these sources. This research is a descriptive-analytical method and library and document collection method. Does this research seek to answer two questions? A: What are the sources of religious knowledge? B: What is the relationship between the sources of religious knowledge?
The results of this research show that Kolayni considers priority and preferences in the sources of knowledge that at the moment of conflict is the source of the discourse, and leads to a search through the Holy Qur'an, so that he sees fitrah as the introduction of all affairs and considers reason as the key to the king. He finds that he finds it in all respects and believes that a wise man has the rightful nature of God and uses the wisdom of the sources of the Quran and the Sunnah.