The Book of Occultation — al-Ṭūsī · Hadith 98 (#Ḥadīth #15)
Chapter 11 | Evidence of the Imamate of Imam Musa Kadhim and refutation of Waqifiya
38- قال وحدثني حنان بن سدير عن إسماعيل البزاز قال قال أبو عبد الله عليه السلام: إن صاحب هذا الأمر يلي الوصية وهو ابن عشرين سنة. فقال إسماعيل: فو الله ما وليها أحد قط كان أحدث منه وإنه لفي السن الذي قال أبو عبد الله عليه السلام.
H 38 - Narrated to me Hannan bin Sudair from Ismail [bin Ziyad] Bazzaz that he said: Imam Ja’far Sadiq said: The master of this affair is the executor of the will, while he is twenty years old. After that Ismail said: No one became the executor of the will of Imam Ja’far Sadiq who was younger; and Imam Kadhim was of the age, which Imam Ja’far Sadiq had mentioned.
Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).