(the wife of the Prophet) Messenger of Allah ﷺ used to invoke Allah in the prayer saying "Allahumma inni aʿudhu bika min ʿadhabi l-qabr, wa aʿudhu bika min fitnati l-masihi d-dajjal, wa aʿudhu bika min fitnati l-mahya wa fitnati l-mamat. Allahumma inni aʿudhu bika mina l-ma'thami wa l-maghram. (O Allah, I seek refuge with You from the punishment of the grave, from the afflictions of the imposter- Messiah, and from the afflictions of life and death. O Allah, I seek refuge with You from sins and from debt)." Somebody said to him, "Why do you so frequently seek refuge with Allah from being in debt?" The Prophet ﷺ replied, "A person in debt tells lies whenever he speaks, and breaks promises whenever he makes (them)." ʿAisha also narrated: I heard Messenger of Allah ﷺ in his prayer seeking refuge with Allah from the afflictions of Ad-Dajjal.  

عَنْ عَائِشَةَ زَوْجِ النَّبِيِّ ﷺ أَخْبَرَتْهُ أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ يَدْعُو فِي الصَّلاَةِ اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنْ عَذَابِ الْقَبْرِ وَأَعُوذُ بِكَ مِنْ فِتْنَةِ الْمَسِيحِ الدَّجَّالِ وَأَعُوذُ بِكَ مِنْ فِتْنَةِ الْمَحْيَا وَفِتْنَةِ الْمَمَاتِ اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنَ الْمَأْثَمِ وَالْمَغْرَمِ فَقَالَ لَهُ قَائِلٌ مَا أَكْثَرَ مَا تَسْتَعِيذُ مِنَ الْمَغْرَمِ فَقَالَ إِنَّ الرَّجُلَ إِذَا غَرِمَ حَدَّثَ فَكَذَبَ وَوَعَدَ فَأَخْلَفَ وَعَنِ الزُّهْرِيِّ قَالَ أَخْبَرَنِي عُرْوَةُ أَنَّ عَائِشَةَ ؓ قَالَتْ سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَسْتَعِيذُ فِي صَلاَتِهِ مِنْ فِتْنَةِ الدَّجَّالِ  

I asked Messenger of Allah ﷺ to teach me an invocation so that I may invoke Allah with it in my prayer. He told me to say, "Allahumma inni zalumtu nafsi zulman kathiran, Wala yaghfiru dh-dhunuba illa anta, fa ghfir li maghfiratan min ʿindika, wa r-hamni, innaka anta l-ghafuru r-rahim (O Allah! I have done great injustice to myself and none except You forgives sins, so bestow on me a forgiveness from You, and Have Mercy on me, You are the Forgiver, the Merciful).  

عَنْ أَبِي بَكْرٍ الصِّدِّيقِ ؓ أَنَّهُ قَالَ لِرَسُولِ اللَّهِ ﷺ عَلِّمْنِي دُعَاءً أَدْعُو بِهِ فِي صَلاَتِي قَالَ قُلِ اللَّهُمَّ إِنِّي ظَلَمْتُ نَفْسِي ظُلْمًا كَثِيرًا وَلاَ يَغْفِرُ الذُّنُوبَ إِلاَّ أَنْتَ فَاغْفِرْ لِي مَغْفِرَةً مِنْ عِنْدِكَ وَارْحَمْنِي إِنَّكَ أَنْتَ الْغَفُورُ الرَّحِيمُ