Salat al-Tasbih

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).

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates that the Prophet (peace and blessings be upon him) said to him: "O boy! Shall I not give you something? Shall I not give you a present? Shall I not give you a gift?" I said: "Yes, O Messenger of Allah! May my father and mother be sacrificed for you." The narrator says: I thought that perhaps the Prophet (peace and blessings be upon him) would give me some wealth. He said: "Four rak'ahs which you should pray every day. If you are not able to do that, then pray them once a week; if you are not able to do that either, then pray them once a month; if you are not able to do that either, then pray them once a year; and if you are not able to do that either, then pray them once at some point in your life. You say the takbir and recite Surah al-Fatihah and a surah once, then you 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. Then in bowing you say these words ten times; then when you rise, you say these words ten times; then when you go into prostration, you say these words ten times; then when you rise, you say these words ten times. Then you do the same throughout your prayer. When you have finished, after the tashahhud and before saying the salam, recite: 'O Allah! I ask You for the enabling grace of the people of guidance, the deeds of the people of certainty, the sincerity of those who repent, the resolve of those who are patient, the striving of those who fear, the seeking of those who long, the devotion of the God-fearing, and the insight of the people of knowledge, so that I may keep fearing You. O Allah! I ask You for such fear as will hold me back from disobeying You, so that I may do such acts of obedience to You by which I become deserving of Your pleasure, and so that I may turn to You in sincere repentance out of fear of You, and make my sincerity purely for You out of love for You, and so that I may rely on You in all affairs, having a good opinion of You. Glory be to You, O Creator of the Fire!'" (After this the Prophet (peace and blessings be upon him) said:) "O Ibn Abbas! When you do this, Allah Almighty will forgive all your sins, small and great, old and new, secret and open, deliberate and mistaken."
Al-Tabarani recorded it in al-Mu'jam al-Awsat.

He (al-Tabarani) also recorded from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both)
this narration via Abu al-Jawza', who narrates: Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said to me: "O Abu al-Jawza'! Shall I not give you something? Shall I not give you a present? Shall I not give you a gift?" I replied: "Yes!" He said: I heard the Prophet (peace and blessings be upon him) say: "Whoever prays four rak'ahs"; after this the narrator mentioned the hadith as before, more briefly than this one, and it contains these words: "Whoever prays them, every sin of his, small and great, old and new, will be forgiven, whether it has already happened or is yet to happen."
The first narration contains a narrator, Abd al-Quddus bin Habib, and he is matruk (abandoned); the second contains Yahya bin Uqbah bin Abi al-Ayzar, and he is da'if (weak).