Deuteronomy 8:2-3

AKJV(i) 2 And you shall remember all the way which the LORD your God led you these forty years in the wilderness, to humble you, and to prove you, to know what was in your heart, whether you would keep his commandments, or no. 3 And he humbled you, and suffered you to hunger, and fed you with manna, which you knew not, neither did your fathers know; that he might make you know that man does not live by bread only, but by every word that proceeds out of the mouth of the LORD does man live.