Muslim - meaning bin Abi Bakrah - narrated that:
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.