John Wesley on Exodus 16:4

Man being made out of the earth, his Maker has wisely ordered him food out of the earth, Psa 104:14. But the people of Israel typifying the church of the first - born that are written in heaven, receiving their charters, laws and commissions from heaven, from heaven also they received their food. See what God designed in making this provision for them, that I may prove them whether they will walk in my law or no - Whether they will trust me, and whether they would serve him, and be ever faithful to so good a master.