He heard his father say following the prayer: "Allahumma inni a'udhu bika minal-kufri wal-faqri, wa 'adhabil-qabri (O Allah, I seek refuge with You from Kufr, poverty and the torment of the grave.)" I started to recite them and he said: "O my son, where did you learn these words?" I said: "O my father, I heard you saying this supplication at the end of the prayer, and I learned them from you." He said: "Continue to recite them, O my son, for the Prophet of Allah [SAW] used to say this supplication at the end of the prayer."
سَمِعَ وَالِدَهُ يَقُولُ فِي دُبُرِ الصَّلاَةِ اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنَ الْكُفْرِ وَالْفَقْرِ وَعَذَابِ الْقَبْرِ فَجَعَلْتُ أَدْعُو بِهِنَّ فَقَالَ يَا بُنَىَّ أَنَّى عُلِّمْتَ هَؤُلاَءِ الْكَلِمَاتِ قُلْتُ يَا أَبَتِ سَمِعْتُكَ تَدْعُو بِهِنَّ فِي دُبُرِ الصَّلاَةِ فَأَخَذْتُهُنَّ عَنْكَ قَالَ فَالْزَمْهُنَّ يَا بُنَىَّ فَإِنَّ نَبِيَّ اللَّهِ ﷺ كَانَ يَدْعُو بِهِنَّ فِي دُبُرِ الصَّلاَةِ