Musnad Ahmad 30:3173

I read to Abd al-Rahman: Malik, from Yazid ibn Abdullah ibn al-Had, from Muhammad ibn Ibrahim ibn al-Harith al-Taymi, from Abu Salamah ibn Abd al-Rahman, from Abu Hurayrah, that he said: I went out to Mount Sinai and met Ka’b al-Ahbar, and I sat with him. He spoke to me about the Torah, and I spoke to him about the Messenger of Allah, may Allah bless him and grant him peace. Among what I told him was that I said: The Messenger of Allah, may Allah bless him and grant him peace, said: "The best day upon which the sun has risen is Friday; on it Adam was created, on it he was made to descend, on it his repentance was accepted, on it he died, and on it the Hour will be established. There is no creature but that it is listening attentively on Friday from the time it wakes until the sun rises, out of fear of the Hour, except for the jinn and mankind. And in it is an hour; no Muslim servant encounters it while he is praying, asking Allah for something, but He gives it to him." Ka’b said: "That is once every year." I said: "Rather, it is every Friday." Ka’b read the Torah and said: "The Messenger of Allah, may Allah bless him and grant him peace, spoke the truth." Abu Hurayrah said: Then I met Abdullah ibn Salam and told him about my sitting with Ka’b and what I had told him regarding Friday. I said to him: Ka’b said, "That is one day every year." Abdullah ibn Salam said: "Ka’b lied." Then Ka’b read the Torah and said: "Rather, it is every Friday." Abdullah ibn Salam said: "Ka’b spoke the truth."