Exodus 16:4, 8

Then the LORD said to Moses, “I will rain down bread from heaven for you. The people are to go out each day and gather enough for that day. In this way I will test them and see whether they will follow my instructions.

Moses also said, “You will know that it was the LORD when he gives you meat to eat in the evening and all the bread you want in the morning, because he has heard your grumbling against him. Who are we? You are not grumbling against us, but against the LORD.”