Exodus 16:32 Moses said, "This is the thing which Yahweh has commanded,'Let an omer-full of it be kept throughout your generations, that they may see the bread with which I fed you in the wilderness, when I brought you forth from the land of Egypt.'" (WEB)
Exodus 16:33 Moses said to Aaron, "Take a pot, and put an omer-full of manna in it, and lay it up before Yahweh, to be kept throughout your generations." (WEB)