أَلَا بِذِكْرِ اللَّهِ تَطْمَئِنُّ الْقُلُوبُ
"Verily, in the remembrance of Allah do hearts find rest."
Reflection
This is perhaps the most powerful verse about peace of mind. "Tatma'innu" — the heart settles, calms, finds satisfaction. No therapy, no distraction, no worldly solution can match what dhikr (remembrance of Allah) does for a troubled heart. When nothing else works, return to His name.