Exodus 16:4-6

4Then the Lord said to Moses, ‘I will cause bread to fall down from the sky for you like rain. Each day, the people must go out and pick up enough bread for that day. In this way I will test them. I will discover whether they will obey my rules.

5On the sixth day, they must pick up and prepare twice as much bread.’

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