It was narrated that Ka'b bin 'Ujrah said:"The Messenger of Allah (ﷺ) said: 'There are statements of remembrance following the prayer of which the one who says them will never be deprive of the reward: Glorifying Allah (SWT) thirty-three times following each prayer, and praising Him thirty-three times, and magnifying Him thirty-four times.'"
أَخْبَرَنَا مُحَمَّدُ بْنُ إِسْمَاعِيلَ بْنِ سَمُرَةَ، عَنْ أَسْبَاطٍ، قَالَ حَدَّثَنَا عَمْرُو بْنُ قَيْسٍ، عَنِ الْحَكَمِ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي لَيْلَى، عَنْ كَعْبِ بْنِ عُجْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مُعَقِّبَاتٌ لاَ يَخِيبُ قَائِلُهُنَّ يُسَبِّحُ اللَّهَ فِي دُبُرِ كُلِّ صَلاَةٍ ثَلاَثًا وَثَلاَثِينَ وَيَحْمَدُهُ ثَلاَثًا وَثَلاَثِينَ وَيُكَبِّرُهُ أَرْبَعًا وَثَلاَثِينَ " .
Nesai
The Book of Forgetfulness (In Prayer) • Hadith 1349