Musnad Ahmad 30:3141

Yunus narrated to us, he said: Al-Khazraj narrated to us, from Abu Ayyub, from Abu Hurairah, he said: I entered the mosque with him on a Friday, and he saw a young boy, so he said to him: "O young boy, go play." He said: "I only came to the mosque." He said: "O young boy, go play." He said: "I only came to the mosque." He said: "So you will sit until the Imam comes out?" He said: "Yes." He said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Indeed, the angels come on the day of Friday, and they sit at the doors of the mosque, and they write down the first, and the second, and the third, and the people according to their ranks until the Imam comes out. So when the Imam comes out, the scrolls are folded."