Deuteronomy 8:2-4

2And thou shalt remember all the way which Yhwh thy God led thee these forty years in the wilderness, to humble thee, and to prove thee, to know what was in thine heart, whether thou wouldest keep his commandments, or no.

3And he humbled thee, and suffered thee to hunger, and fed thee with manna, which thou knewest not, neither did thy fathers know; that he might make thee know that man doth not live by bread only, but by every word that proceedeth out of the mouth of Yhwh doth man live.

4Thy raiment waxed not old upon thee, neither did thy foot swell, these forty years.