حَسْبُنَا اللَّهُ وَنِعْمَ الْوَكِيلُ
Hasbunal-lahu waniAAmal-wakeel
Translation
Allah is sufficient for us and He is the best disposer of affairs.
When to recite
Recited when faced with a difficult situation or an adversary. This was said by Ibrahim (AS) when thrown into the fire, and by the Prophet Muhammad (SAW) when told the enemy had gathered against him.
Source / Reference
Quran 3:173, Al-Bukhari 5/172