Fath al-Rabbani

Syedna Abu Saeed Khudri (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him and his family) performed i'tikaf during the middle ten days of Ramadan before the clarification regarding Laylat al-Qadr. When this ten-day period ended, he ordered his tent to be dismantled, so it was dismantled. Afterwards, it became clear to him that the night (Laylat al-Qadr) was in the last ten days. Then he ordered that the tent be set up again, so it was set up again. Thus, he performed i'tikaf during the last ten days. Then he came to the people and said: O people! I was informed with certainty about Laylat al-Qadr and I was coming to inform you, but it happened that two men were arguing, and Satan was with them, so I was made to forget that knowledge. Now, seek this night in the odd nights of the ninth, seventh, and fifth (from the end). I (Abu Nadrah) said: O Abu Saeed! You know counting better than us. He said: We (being companions) are more deserving of it than you. I said: What is meant by the ninth, seventh, and fifth night? He said: The night which you call the twenty-first night, leave it; the next night after that is the ninth. The night which you call the twenty-third night, leave it; the next night after that is the seventh. And the night which you call the twenty-fifth night, leave it; the next night after that is the fifth.