28الَّذينَ آمَنوا وَتَطمَئِنُّ قُلوبُهُم بِذِكرِ اللَّهِ ۗ أَلا بِذِكرِ اللَّهِ تَطمَئِنُّ القُلوبُ(Irfan-ul-Quran)Those who believe and their hearts become calm and contented with the remembrance of Allah — know that it is the remembrance of Allah alone that brings calm to the hearts.