“In the time of the Sixth Imam, the conditions for spreading Islamic knowledge were more favorable and the circumstances were better. On the one hand, due to the dissemination of the Hadiths of Imam Muhammad al-Baqir (peace be upon him) and the efforts of his disciples, the people became more aware of their need for Islamic knowledge and the teachings of the Ahl al-Bayt (peace be upon them). They became more eager to learn Hadith. On the other hand, the Umayyad dynasty had collapsed, and the Abbasid rule had not yet fully established itself. The Abbasids, in their efforts to achieve their goals and overthrow the Umayyad government, used the victimhood of the Ahl al-Bayt (peace be upon them) and the blood of the martyrs of Karbala as a means to gain support, which made them appear favorable toward the Ahl al-Bayt (peace be upon them).
Imam Jafar al-Sadiq (peace be upon him) thus engaged in spreading various sciences, and scholars and learned individuals from all directions gathered at his door. They sought his presence and asked questions regarding various branches of Islamic knowledge, ethics, history of the Prophets and nations, wisdom, and preaching, receiving answers in return.
He engaged in discussions with different groups and debated with various sects, and in many fields of science, he nurtured students. As a result of his efforts, thousands of scholars from religious circles, who were experts in various fields of knowledge, spread across the world, disseminating knowledge. Hundreds of books were written to document his Hadiths and scientific statements, which are collectively referred to as the ‘Usul’ (Principles).
The Shi’a, who follow the method of the Ahl al-Bayt (peace be upon them), cleared all ambiguities in their religious goals and matters thanks to the blessings of the Imam. They resolved their religious uncertainties with his healing words. For this reason, the Shi’a sect (which is the same as the sect of the Ahl al-Bayt) became widely known among the people as the Ja’fari school of thought.”
Extracted from the book “Teaching Religion,” by Allama Sayyid Muhammad Hussain Tabatabai (may Allah have mercy on him) (with slight modifications).