Deuteronomy 8:15-17

who led thee through that great and terrible wilderness, wherein were fiery serpents, and scorpions, and drought, where there was no water; who brought thee forth water out of the rock of flint; who fed thee in the wilderness with manna, which thy fathers knew not, that he might humble thee, and that he might prove thee, to do thee good at thy latter end; and thou say in thine heart, My power and the might of mine hand hath gotten me this wealth.