Musnad Ahmad 32:669

Husayn narrated to us, Khalaf narrated to us, from Hafs ibn Umar, from Anas, who said: I was sitting with the Messenger of Allah, peace and blessings of Allah be upon him, in the circle when a man came and greeted the Prophet, peace and blessings of Allah be upon him, and the people. The man said: "Peace be upon you, and the mercy of Allah." The Prophet, peace and blessings of Allah be upon him, replied: "And upon you be peace, and the mercy of Allah, and His blessings." When the man sat down, he said: "Praise be to Allah, a praise that is abundant, good, and blessed therein, as our Lord loves to be praised, and as befits Him." The Prophet, peace and blessings of Allah be upon him, said to him: "What did you say?" He repeated to him what he had said. The Prophet, peace and blessings of Allah be upon him, said: "By the One in Whose hand is my soul, ten angels hastened to it, each of them eager to write it down. They did not know how to write it, so they raised it to the Possessor of Might, and He said: 'Write it down just as My servant said.'"