Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates: Once Sayyiduna al-Abbas (may Allah be pleased with him) came to the Prophet (peace and blessings be upon him) at an hour in which he did not usually come to him. It was said: "O Messenger of Allah! Your uncle is at the door." The Prophet (peace and blessings be upon him) said: "Tell him to come in; he must have come for some important matter." When Sayyiduna al-Abbas (may Allah be pleased with him) came in to the Prophet (peace and blessings be upon him), the Prophet (peace and blessings be upon him) said: "O dear uncle! Why have you come at this time? You did not use to come at this hour before." Sayyiduna al-Abbas (may Allah be pleased with him) said: "O my nephew! I remembered the Days of Ignorance and its ignorant ways, and the world, despite all its vastness, became narrow for me. I thought: How can I find relief from this? Then I realised that no one can give me relief from this except Allah Almighty, or else you." The Prophet (peace and blessings be upon him) said: "All praise belongs to Allah Almighty, who has put this into your heart. My wish was that Abu Talib too had obtained his share, but Allah Almighty does whatever He wills." The Prophet (peace and blessings be upon him) said: "Shall I tell you about it?" He said: "Yes!" The Prophet (peace and blessings be upon him) said: "Shall I give you a gift?" He said: "Yes!" The Prophet (peace and blessings be upon him) said: "Shall I give you something?" He said: "Yes!" The Prophet (peace and blessings be upon him) said: "When there is a time in which you are able to pray, that is, not after Asr and not after sunrise, then perform ablution thoroughly in it, then stand before Allah Almighty and recite Surah al-Fatihah; then, if you wish, recite a surah, and if you wish, recite one of the opening surahs of the Mufassal. When you have finished reciting the surah, say 'Subhan Allah, wal-hamdu lillah, wa la ilaha illallah, wallahu akbar' (Glory be to Allah, all praise is for Allah, there is no god but Allah, and Allah is the Greatest) fifteen times. When you go into bowing, say it ten times, and when you raise your head, say it ten times."
(Allamah al-Haythami says:) I say: Imam Abu Dawud and others recorded this narration without this context.
Al-Tabarani recorded it in al-Mu'jam al-Kabir. Its chain contains a narrator, Nafi' bin Hurmuz, and he is da'if (weak).