Ibn Hibban

Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrates: The Prophet Muhammad (peace and blessings be upon him) performed i'tikaf in the first ten days of Ramadan. Then he performed i'tikaf in the middle ten days in a Turkish tent, at the door of which a piece of mat was hanging. The narrator says: The Prophet (peace and blessings be upon him) took hold of the mat with his blessed hand and hung it on one side of the tent. Then he put his head out to talk to the people. The people came close to him. He said: I performed i'tikaf in the first ten days seeking this night, then I performed i'tikaf in the middle ten days, then an angel came to me and I was informed that it is in the last ten nights, so whoever among you wishes to perform i'tikaf should do so. (The narrator says) The people performed i'tikaf with him, so the Prophet (peace and blessings be upon him) said: I saw this night, and in its morning I was prostrating in water and mud. On the morning of the twenty-first night, when the Prophet (peace and blessings be upon him) stood up to perform the morning prayer, it started to rain and the roof of the mosque began to leak. I saw the mud getting wet. When the Prophet (peace and blessings be upon him) finished the morning prayer and came out, there was a mark of water and mud on his blessed forehead and blessed nose. This was the morning after the twenty-first night of the last ten days.