Exodus 16:33-36

33And Moses said to Aaron, “Take a pot and put an omer of manna in it, and lay it up before the Lord, to be kept for your generations.”

34As the Lord commanded Moses, so Aaron laid it up before the Testimony, to be kept.

35And the children of Israel ate manna forty years, until they came to an inhabited land; they ate manna until they came to the border of the land of Canaan.

36Now an omer is one-tenth of an ephah.