Thirty-three, thirty-three, thirty-four
Said after every prescribed prayer, and the sins fall away though they were like the foam of the sea.
مَنْ سَبَّحَ اللَّهَ فِي دُبُرِ كُلِّ صَلاَةٍ ثَلاَثًا وَثَلاَثِينَ وَحَمِدَ اللَّهَ ثَلاَثًا وَثَلاَثِينَ وَكَبَّرَ اللَّهَ ثَلاَثًا وَثَلاَثِينَ فَتِلْكَ تِسْعَةٌ وَتِسْعُونَ وَقَالَ تَمَامَ الْمِائَةِ لاَ إِلَهَ إِلاَّ اللَّهُ وَحْدَهُ لاَ شَرِيكَ لَهُ لَهُ الْمُلْكُ وَلَهُ الْحَمْدُ وَهُوَ عَلَى كُلِّ شَىْءٍ قَدِيرٌ غُفِرَتْ خَطَايَاهُ وَإِنْ كَانَتْ مِثْلَ زَبَدِ الْبَحْرِ
Subḥāna-llāh (×33), al-ḥamdu lillāh (×33), Allāhu akbar (×33), then: lā ilāha illa-llāhu waḥdahu lā sharīka lah, lahu-l-mulku wa lahu-l-ḥamd, wa huwa ʿalā kulli shay'in qadīr.
“Glory be to Allah, thirty-three times. Praise be to Allah, thirty-three times. Allah is greatest, thirty-three times. Then, completing the hundred: there is no god but Allah alone, with no partner. To Him belongs the dominion and to Him is praise, and He is over all things capable.”
The full narration
Abu Huraira reported Allah's Messenger (ﷺ) as saying:If anyone extols Allah after every prayer thirty-three times, and praises Allah thirty-three times, and declares His Greatness thirty-three times, ninety-nine times in all, and says to complete a hundred:" There is no god but Allah, having no partner with Him, to Him belongs sovereignty and to Him is praise due, and He is Potent over everything," his sins will be forgiven even If these are as abundant as the foam of the sea
Source
Ṣaḥīḥ Muslim · 1352
- Agreed upon as authentic (al-Bukhārī / Muslim)