Exodus 16:23-30
[Moses] said to [the children of Israel]: “This is what Jehovah said: ‘Tomorrow is the holy Sabbath, My day of rest. Bake today what you will bake, cook what you will cook and set the leftovers aside for the Sabbath.'”
And when the children of Israel saved the leftovers as Moses commanded, it did not spoil, nor become infested with worms.
Moses then said on the Sabbath: “Eat the leftovers today, for today is Sabbath to Jehovah, today you will not find it in the field. Six days you shall gather it, but the seventh day is the Sabbath. On it there will not be any.”
And it came to pass on the seventh day, some went out to gather it and they found none. And Jehovah said to Moses, “How long will they refuse to keep my commandments and my laws? I have given the Sabbath, therefore I give you on the sixth day the bread for two days.
Abide every man in his place: let no man go from his place on the seventh day.” And the people rested on the seventh day.