عَنْ أَبِي عُبَيْدَةَ عَنْ عَبْدِ اللَّهِ رَضِيَ اللَّهُ عَنْهُ قَالَ لَمَّا أُنْزِلَ عَلَى رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ إِذَا جَاءَ نَصْرُ اللَّهِ وَالْفَتْحُ [النصر: 1] كَانَ يُكْثِرُ إِذَا قَرَأَهَا وَرَكَعَ أَنْ يَقُولَ سُبْحَانَكَ اللَّهُمَّ رَبَّنَا وَبِحَمْدِكَ اللَّهُمَّ اغْفِرْ لِي إِنَّكَ أَنْتَ التَّوَّابُ الرَّحِيمُ ثَلَاثًا
It is narrated from Sayyiduna Abdullah (may Allah be pleased with him) that when Surah An-Nasr was revealed to the Noble Prophet (peace and blessings be upon him), it mostly happened that whenever he (peace and blessings be upon him) recited this Surah, he would recite this supplication three times in bowing (ruku’): Subhanak Allahumma Rabbana wa bihamdika Allahumma ighfir li innaka anta at-Tawwab ar-Raheem. (O Allah! You are pure, O our Lord! And with Your praise, O Allah! Forgive me, surely You are the Acceptor of repentance, the Most Merciful.)