Musnad Ahmad 31:633

Yunus and Surayj narrated to us, they said: Fulayh narrated to us, from Sa’id ibn al-Harith, from Abu Salamah, who said: Abu Hurayrah used to narrate to us from the Messenger of Allah (peace and blessings of Allah be upon him) that he said: "Indeed, there is an hour on Friday; no Muslim coincides with it while he is in prayer, asking Allah for good, but He will grant it to him." He said: And Abu Hurayrah indicated its brevity with his hand. He said: When Abu Hurayrah passed away, I said: By Allah, if I go to Abu Sa’id and ask him about this hour, perhaps he has some knowledge of it. So I went to him and found him straightening palm stalks. I said: O Abu Sa’id, what are these palm stalks that I see you straightening? He said: These are palm stalks in which Allah has placed a blessing for us. The Messenger of Allah (peace and blessings of Allah be upon him) used to love them and lean upon them, so we would straighten them and bring them to him. He saw spittle in the direction of the Qiblah of the mosque, and in his hand was a palm stalk from those stalks, so he scraped it off and said: "When one of you is in his prayer, let him not spit in front of him, for his Lord is in front of him. Let him spit to his left or under his foot. If he does not find a place to spit, then in his garment or his sandal." He said: Then the sky became agitated that night. When the Prophet (peace and blessings of Allah be upon him) went out for the final Isha prayer, a flash of lightning occurred, and he saw Qatadah ibn al-Nu’man. He said: "What is the reason for your traveling at night, O Qatadah?" He said: I knew, O Messenger of Allah, that those attending the prayer are few, so I liked to attend it. He said: "When you finish praying, remain until I pass by you." When he finished, he gave him the palm stalk and said: "Take this, for it will illuminate for you ten [cubits] in front of you and ten behind you. When you enter your house and see a black figure in the corner of the house, strike it before it speaks, for it is a devil." He said: So he did, and we love these palm stalks for that reason. He said: I said: O Abu Sa’id, Abu Hurayrah narrated to us about the hour that is on Friday, do you have any knowledge of it? He said: I asked the Prophet (peace and blessings of Allah be upon him) about it, and he said: "I had been informed of it, then I was made to forget it, just as I was made to forget the Night of Decree (Laylat al-Qadr)." He said: Then I left him and entered upon Abdullah ibn Salam.