A Powerful Prayer for Steadfastness of Heart in Faith and Avoiding Deviation

Peace be upon you and God's mercy and blessings. One of the most beautiful prayers that preserves the heart and keeps it firm on guidance is the prayer from Surah Ali 'Imran, verse 8: "Our Lord, let not our hearts deviate after You have guided us and grant us from Yourself mercy. Indeed, You are the Bestower." God Almighty says in the preceding verse (verse 7) about those in whose hearts is deviation: "It is He who has sent down to you, [O Muhammad], the Book; in it are verses [that are] precise - they are the foundation of the Book - and others unspecific." So, praying for steadfastness in faith is a protection from deviation and misguidance, especially in times of trials and ambiguities. O God, make our hearts firm in Your religion and do not let them deviate after You have guided us.