Deuteronomy 8:2

8:2 Remember the whole way by which he has brought you these forty years through the desert so that he might, by humbling you, test you to see if you have it within you to keep his commandments or not.

Deuteronomy 8:15-16

8:15 and who brought you through the great, fearful desert of venomous serpents and scorpions, an arid place with no water. He made water flow from a flint rock and 8:16 fed you in the desert with manna (which your ancestors had never before known) so that he might by humbling you test you and eventually bring good to you.