It is narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) used to observe i'tikaf in the middle ten days (the second ten days) of Ramadan. Then one year he observed i'tikaf, and when the twenty-first night came, on the morning of which he (peace be upon him) would come out of i'tikaf, he (peace be upon him) said: "Whoever has observed i'tikaf with me should continue and observe i'tikaf for the last ten days (the third ten days), and I was made to know about Laylat al-Qadr, then I was made to forget it. I think I saw myself prostrating on the morning of Laylat al-Qadr in mud and water. So seek it in the last ten nights, in every odd night." Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) said that on that very night it rained, and the roof of the mosque was made of leaves and branches, so the mosque dripped. Sayyiduna Abu Sa'id (may Allah be pleased with him) said: My two eyes saw the Messenger of Allah (peace and blessings of Allah be upon him), he finished the prayer and there was a mark of mud and water on his blessed forehead and nose, on the morning of the twenty-first night.