Exodus 16:27

They laid it up until the morning, as Moses ordered, and it didn’t become foul, and there were no worms in it.

Moses said, “Eat that today, for today is a Sabbath to the LORD. Today you shall not find it in the field.

Six days you shall gather it, but on the seventh day is the Sabbath. In it there shall be none.”

The LORD said to Moses, “How long do you refuse to keep my commandments and my laws?

Behold, because the LORD has given you the Sabbath, therefore he gives you on the sixth day the bread of two days. Everyone stay in his place. Let no one go out of his place on the seventh day.”

So the people rested on the seventh day.