Everything in this book that is narrated from Abdur Rahman ibn Al-Hajjaj has been transmitted by me from Ahmad ibn Muhammad ibn Yahya Al-Attar - may Allah سبحانه وتعالى be pleased with him - from his father, from Ahmad ibn Muhammad ibn Isa, from Ibn Abi Umayr and Al-Hasan ibn Mahbub together, from Abdur Rahman ibn Al-Hajjaj Al-Bajali Al-Kufi. He was a freed servant (mawla) who met Imam Al-Sadiq and Imam Musa ibn Jafar (peace be upon them) and narrated from both of them. Imam Musa عليه السلام, when Abdur Rahman was mentioned in his presence, would say: "Indeed, he weighs heavily on the heart."