Exodus 16
32 Ref And Moses said, This is the order which the Lord has given: Let one omer of it be kept for future generations, so that they may see the bread which I gave you for your food in the waste land, when I took you out from the land of Egypt.
33 Ref And Moses said to Aaron, Take a pot and put one omer of manna in it, and put it away before the Lord, to be kept for future generations.