O Allah, O Turner of hearts, make my heart firm upon Your religion. — After Prayer Adhkar

اللَّهُمَّ يَا مُقَلِّبَ الْقُلُوبِ ثَبِّتْ قَلْبِي عَلَى دِينِكَ

Transliteration: Allaahumma yaa muqallibal-quloobi thabbit qalbee 'alaa deenik

Translation: O Allah, O Turner of hearts, make my heart firm upon Your religion.