Narrated ibn Abbas radi Allaahu `anhuma:

(The saying) “Allaah (Alone) is Sufficient for us, and He is the Best Disposer of affairs (for us)” was said by Ibraahiim `alehi wa salaam when he was thrown into the fire; and it was said by Muhammad sala Allahu `alehi wa salaam when they (the hypocrites) said, “Verily, the people (pagans) have gathered against you (a great army), therefore, fear them”, but it (only) increased them in Faith and they said “Allaah (Alone) is Sufficient for us, and He is the Best Disposer of affairs (for us).”