His son al-Sādiq (1)—peace be upon him—was the finest and most devout man of his age. The biographers (2) said that his devotion to worship kept him from seeking leadership.

Umar ibn Abī al-Miqdām said:

“Whenever I looked at Ja'far ibn Muhammad al-Sādiq (3), I knew that he was descended from the prophets. It was he who disseminated Imāmī jurisprudence, true knowledge, and doctrines of certainty. Whenever he foretold something, it came to pass; for this reason, they called him al-Sādiq al-Amīn—the Truthful and Trustworthy.”

Abd Allāh ibn al-Hasan (4) had gathered the leading Alids (5) so that allegiance might be pledged to his two sons. Al-Sādiq (6) said, “This (7) bid for rule will not succeed.” This caused anger. He then said, “It belongs to the man in the yellow cloak,” by which he meant al-Mansūr. When al-Mansūr heard this, he rejoiced, for he knew that whatever al-Sādiq foretold would come to pass (8), and he knew that rule would pass to him (9). While in flight, he would say, “What has become of the words of their Truthful One?” Thereafter, rule did pass to him.

His son Mūsā al-Kāzim (10) was known as the Righteous Servant. He was the most devout man of his time (11), standing in prayer by night and fasting by day. He was called al-Kāzim because, whenever he (12) heard something about