Majma al-Zawaid — Hadith 5041

Sayyiduna Ubadah bin al-Samit (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Laylat al-Qadr is in the remaining ten nights. Whoever stands in voluntary prayer in those nights hoping for their reward, Allah Almighty will forgive his past and future sins. It is an odd night: the ninth, or the seventh, or the fifth, or the third, or the last night." The Prophet (peace and blessings be upon him) said: "The distinctive sign of Laylat al-Qadr is that it is clear and bright, the moon will be shining in it, it is a still and moderate night, with neither cold nor heat in it, and no star will be shot in it until morning comes. And its distinctive sign is that on the following morning, when the sun rises, it is perfectly even, without rays, like the moon of the fourteenth night. On that day it is not permitted for Satan to come out with it."
Ahmad recorded it, and its narrators are thiqat (trustworthy).