When Messenger of Allah ﷺ fought the battle of Khaibar, or when Messenger of Allah ﷺ went towards it, (whenever) the people, (passed over a high place overlooking a valley, they raised their voices saying, "Allahu-Akbar! Allahu-Akbar! None has the right to be worshipped except Allah." On that Allah's Apostle said (to them), "Lower your voices, for you are not calling a deaf or an absent one, but you are calling a Hearer Who is near and is with you." I was behind the riding animal of Messenger of Allah ﷺ and he heard me saying. "There Is neither might, nor power but with Allah," On that he said to me, "O ʿAbdullah bin Qais!" I said, "Labbaik. O Messenger of Allah ﷺ!" He said, "Shall I tell you a sentence which is one of the treasures of Paradise" I said, "Yes, O Messenger of Allah ﷺ! Let my father and mother be sacrificed for your sake." He said, "It is: There is neither might nor power but with Allah."  

عَنْ أَبِي مُوسَى الأَشْعَرِيِّ ؓ قَالَ لَمَّا غَزَا رَسُولُ اللَّهِ ﷺ خَيْبَرَ أَوْ قَالَ لَمَّا تَوَجَّهَ رَسُولُ اللَّهِ ﷺ أَشْرَفَ النَّاسُ عَلَى وَادٍ فَرَفَعُوا أَصْوَاتَهُمْ بِالتَّكْبِيرِ اللَّهُ أَكْبَرُ اللَّهُ أَكْبَرُ لاَ إِلَهَ إِلاَّ اللَّهُ فَقَالَ رَسُولُ اللَّهِ ﷺ ارْبَعُوا عَلَى أَنْفُسِكُمْ إِنَّكُمْ لاَ تَدْعُونَ أَصَمَّ وَلاَ غَائِبًا إِنَّكُمْ تَدْعُونَ سَمِيعًا قَرِيبًا وَهْوَ مَعَكُمْ وَأَنَا خَلْفَ دَابَّةِ رَسُولِ اللَّهِ ﷺ فَسَمِعَنِي وَأَنَا أَقُولُ لاَ حَوْلَ وَلاَ قُوَّةَ إِلاَّ بِاللَّهِ فَقَالَ لِي يَا عَبْدَ اللَّهِ بْنَ قَيْسٍ قُلْتُ لَبَّيْكَ رَسُولَ اللَّهِ قَالَ أَلاَ أَدُلُّكَ عَلَى كَلِمَةٍ مِنْ كَنْزٍ مِنْ كُنُوزِ الْجَنَّةِ قُلْتُ بَلَى يَا رَسُولَ اللَّهِ فِدَاكَ أَبِي وَأُمِّي قَالَ لاَ حَوْلَ وَلاَ قُوَّةَ إِلاَّ بِاللَّهِ  

Abu Bakr As-Siddiq said to the Prophet ﷺ "O Messenger of Allah ﷺ! Teach me an invocation with which I may invoke Allah in my prayers." The Prophet ﷺ said, "Say: O Allah! I have wronged my soul very much (oppressed myself), and none forgives the sins but You; so please bestow Your Forgiveness upon me. No doubt, You are the Oft-Forgiving, Most Merciful."  

أَنَّ أَبَا بَكْرٍ الصِّدِّيقَ ؓ قَالَ لِلنَّبِيِّ ﷺ يَا رَسُولَ اللَّهِ عَلِّمْنِي دُعَاءً أَدْعُو بِهِ فِي صَلاَتِي قَالَ قُلِ اللَّهُمَّ إِنِّي ظَلَمْتُ نَفْسِي ظُلْمًا كَثِيرًا وَلاَ يَغْفِرُ الذُّنُوبَ إِلاَّ أَنْتَ فَاغْفِرْ لِي مِنْ عِنْدِكَ مَغْفِرَةً إِنَّكَ أَنْتَ الْغَفُورُ الرَّحِيمُ