The Book of Occultation — al-Ṭūsī · Hadith 774 (#Ḥadīth #23)
Chapter 52 | Some Qualities, practices and manners of the Master of the Age
505- الفضل بن شاذان، عن الحسن بن محبوب، عن عمرو بن أبي المقدام، عن جابر الجعفي قال:سمعت أبا جعفر عليه السلام يقول: والله، ليملكن منا أهل البيت رجل بعد موته ثلاثمائة سنة يزداد تسعا. قلت:متى يكون ذلك؟ قال: بعد القائم عليه السلام. قلت: وكم يقوم القائم في عالمه؟ قال: تسع عشرة سنة،ثم يخرج المنتصر فيطلب بدم الحسين عليه السلام ودماء أصحابه، فيقتل ويسبي حتى يخرج السفاح.
H 505 - Narrated Fadhl bin Shazan from Hasan bin Mahbub from Amr bin Abil Miqdam from Ja’far Jofi that he heard Imam Muhammad Baqir say: “By Allah, after the passing away of Imam Qaim, a person from us Ahle Bayt will rule for three hundred and nine years.” I asked: “When will this be?” He replied: “After the Qaim.” I asked: “For how many years will Imam Qaim rule after reappearance?” He replied: “Nineteen years. After that Muntasir [Imam Husain ] will return (do Rajat) and he will eliminate the enemies of Imam Husain in revenge till Saffah [Amirul Momineen ] will do Rajat.” Praise be to Allah, the Mighty and the High, the book has reached completion. Benedictions and salutations of Almighty Allah be on Muhammad and his chosen Progeny; the ones, from whom Almighty Allah has kept away all impurities and has purified them as it deserves.
Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).