Sunan al-Nasa'i
The Book of Forgetfulness (In Prayer) — Hadith #1349
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا يَحْيَى، عَنْ عُثْمَانَ الشَّحَّامِ، عَنْ مُسْلِمِ بْنِ أَبِي بَكْرَةَ، قَالَ كَانَ أَبِي يَقُولُ فِي دُبُرِ الصَّلاَةِ اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنَ الْكُفْرِ وَالْفَقْرِ وَعَذَابِ الْقَبْرِ فَكُنْتُ أَقُولُهُنَّ فَقَالَ أَبِي أَىْ بُنَىَّ عَمَّنْ أَخَذْتَ هَذَا قُلْتُ عَنْكَ . قَالَ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَقُولُهُنَّ فِي دُبُرِ الصَّلاَةِ .
“My father used to say following every prayer: ‘Allahumma inni a-udhu bika min al-kufri wal-faqri wa ‘adhab al-qabr. ( O Allah, I seek refuge with You from Kufr, poverty, and the torment of the grave)’ and I used to say them (these words). My father said: ‘O my son, from whom did you learn this?’ I said: ‘From you. He said: “The Messenger of Allah (ﷺ) used to say them following the prayer.'”
Chain of Narration (Isnad)