Exodus 16:4-6

4The Lord said to Moses, “I’m going to send you food from heaven like rain. Each day the people should go out and gather only what they need for that day. In this way I will test them to see whether or not they will follow my instructions.

5But on the sixth day when they prepare what they bring home, it should be twice as much as they gather on other days.”

6So Moses and Aaron said to all the Israelites, “In the evening you will know that it was the Lord who brought you out of Egypt.