Deuteronomy 8:16-18

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 lest thou say in thy heart, My power and the might of my hand hath gotten me this wealth. But thou shalt remember Jehovah thy God, for it is he that giveth thee power to get wealth; that he may establish his covenant which he sware unto thy fathers, as at this day.