Mu'jam Kabir Tabarani 9546 — I said, O Abu al-Mundhir - meaning I said

Zirr bin Hubaysh said: I said, "O Abu al-Mundhir" - meaning I said to Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) - "tell me about Laylat al-Qadr, for Ibn Umm Abd (Sayyiduna Ibn Mas'ud (may Allah be pleased with him)) says: Whoever stands (in night prayer) the whole year will find it." He said: "May Allah have mercy on Abu Abd al-Rahman; he knows that it is in Ramadan, but he kept the matter vague for the people so that they would not talk (about it). By the One who sent down the Book upon Muhammad (peace and blessings be upon him), it is indeed in Ramadan, and it is the twenty-seventh night." I said: O Abu al-Mundhir, how did you come to know that? He said: "By the sign that the Messenger of Allah (peace and blessings be upon him) told us of; we have seen it and remembered it. By Allah, it is indeed that (night)" - he swore without saying 'In sha' Allah'. I asked Zirr: What is the sign? He said: "On that morning the sun rises as though it were a basin, with no strong rays."