And when Ibrahim said: My Lord! show me how Thou givest life to the dead, He said: What! and do you not believe? He said: Yes, but that my heart may be at ease. He said: Then take four of the birds, then train them to follow you, then place on every mountain a part of them, then call them, they will come to you flying; and know that Allah is Mighty, Wise.

Those who believe and whose hearts are set at rest by the remembrance of Allah; now surely by Allah's remembrance are the hearts set at rest.

He who disbelieves in Allah after his having believed, not he who is compelled while his heart is at rest on account of faith, but he who opens (his) breast to disbelief-- on these is the wrath of Allah, and they shall have a grievous chastisement.