Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: Sayyiduna Umar (may Allah be pleased with him) used to ask my opinion along with the Companions of the Messenger of Allah (peace and blessings be upon him). Abd al-Rahman bin Awf (may Allah be pleased with him) said to him: Do you ask him too? He said: He is from where you know. So he asked them about the surah "When the help of Allah and the victory comes" [Surah al-Nasr: 1], and I said: It is only (the announcement of) the appointed time of the Prophet's (peace and blessings be upon him) death. And I recited the whole surah up to "He is ever accepting of repentance" [Surah al-Nisa: 16], and Sayyiduna Umar (may Allah be pleased with him) said: You have spoken the truth.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10570