بسم الله الواحد القهار
The testament of Amirul-Muminin Ali(عليه السلام) is a famous event that he(عليه السلام) let some people to witness, so it has been narrated through many chains in both Shia and Non-Shia sources. The oldest record of it goes back to the book of Sulaym Ibn Qays directly from Amirul-Muminin(عليه السلام). It has been narrated through the Imams of Ahlulbayt(عليهم السلام) as well. It has been narrated in our famous books like Al-Kafi of Sheikh Al-Kulayni, Man Laa Yadhur Al-Faqih of Sheikh As-Saduq, Tahdhib Al-Ahkaam of Sheikh At-Tusi and many more. I want to present it here to you from the book Al-Kafi through Imam Al-Kadhim(عليه السلام) who wrote it to one of his companions. The testament is a bit long, so I just cut out a small part of it where Amirul-Muminin(عليه السلام) talks about the companions of the Prophet(صلی الله وعليه وآله).Sheikh Al-Kulayni:
Abu Ali al-Ash‘ari has narrated from Mohammad Ibn Abdul-Jabbar and Mohammad Ibn Isma‘il they have narrated from al-Fadhl Ibn Shadhaan from Safwan Ibn Yahya from Abdur-Rahman Ibn Al-Hajjaj who has narrated the following:
“Abu al-Hassan(عليه السلام) sent to me the will of ’Amir al-Mu’minin(عليه السلام) which reads as follows:
" In The Name of Allah, The Most Beneficent, The Most Merciful
...
(I remind you of) Allah, (I remind you of) Allah, about the companions of your Prophet, the companions who did not invent heresy or give protection to heretics, for the Messenger of Allah(صلی الله وعليه وآله) has urged to be good to them, he has condemned the heretics among them and others and also those who protect the heretics."
Al-Kafi, Vol. 7 Pg. 52
Grading: the Chain is Sahih(Authentic).
Check the narrators in the Rijaal section:
70: Ahmad Ibn Idrees, Abu Ali Al-Ash'ari
1684: Mohammad Ibn Abdul-Jabbar (and Mohammad Ibn Isma'il)
1416: Al-Fadhl Ibn Shadhaan Al-Nayshabouri
926: Safwan Ibn Yahya
999: Abdur-Rahman Ibn Al-Hajjaj Al-Bajali
