الَّذينَ آمَنوا وَتَطمَئِنُّ قُلوبُهُم بِذِكرِ اللَّهِ ۗ أَلا بِذِكرِ اللَّهِ تَطمَئِنُّ القُلوبُ

Those who believe and whose hearts find tranquility in the remembrance of God—for indeed, it is through the remembrance of God that hearts find peace.