Qur'an 13:28

ٱلَّذِينَ ءَامَنُوا۟ وَتَطْمَئِنُّ قُلُوبُهُم بِذِكْرِ ٱللَّهِ ۗ أَلَا بِذِكْرِ ٱللَّهِ تَطْمَئِنُّ ٱلْقُلُوبُ

“Those who have believed and whose hearts are assured by the remembrance of Allāh. Unquestionably, by the remembrance of Allāh hearts are assured."”

Ar-Ra'd 13:28 · Saheeh International