Deuteronomy 8:1-3

“Every commandment that I am commanding you today you shall be careful to do, so that you may live and multiply, and go in and possess the land which the LORD swore [to give] to your fathers. And you shall remember [always] all the ways which the LORD your God has led you these forty years in the wilderness, so that He might humble you and test you, to know what was in your heart (mind), whether you would keep His commandments or not. He humbled you and allowed you to be hungry and fed you with manna, [a substance] which you did not know, nor did your fathers know, so that He might make you understand [by personal experience] that man does not live by bread alone, but man lives by every word that proceeds out of the mouth of the LORD.