Musnad Abu Ya'la al-Mawsili 42:103

Wahb ibn Baqiyyah narrated to us, Khalid informed us, from al-Jurayri, from Abu Nadrah, from Abu Sa’id, who said: The Messenger of Allah (peace be upon him) performed I’tikaf during the middle ten days of Ramadan, seeking the Night of Decree. Then he ordered the structure [of his tent] to be taken down, and it was taken down. Then it was made clear to him that it was in the last ten days, so he ordered it to be rebuilt, and it was rebuilt. He came out to us and said: "The Night of Decree was made clear to me, and I came out to clarify it to you, but two men were arguing, so I forgot it. Seek it in the ninth, the seventh, and the fifth." I said: "O Abu Sa’id, you are more knowledgeable about the count than us, so which night is the ninth, the seventh, and the fifth?" He said: "Yes, and we are more entitled to that. When the night of the twenty-first has passed, then skip a night, and the one that follows it is the third. Then skip a night, and the one that follows it is the fifth." Al-Jurayri said: Abu al-‘Ala’ narrated to me from Mutarrif that he heard Mu’awiyah saying: The Messenger of Allah (peace be upon him) said: "And the third..."