Exodus 16:4-5

Then said the LORD unto Moses, Behold, I will rain bread from heaven for you; and the people shall go out and gather a certain rate every day, that I may prove them, whether they will walk in my law, or no. {a certain...: Heb. the portion of a day in his day} And it shall come to pass, that on the sixth day they shall prepare {that} which they bring in; and it shall be twice as much as they gather daily.