exodus 16:32 And Moses said, This is the thing which the LORD commandeth, Fill an omer of it to be kept for your generations; that they may see the bread wherewith I have fed you in the wilderness, when I brought you forth from the land of Egypt. - Free Bible Online

      32-36. Fill an omer of it to be kept for your generations--The mere fact of such a multitude being fed for forty years in the wilderness, where no food of any kind is to be obtained, will show the utter impossibility of their subsisting on a natural production of the kind and quantity as this tarfa-gum [see on Ex 16:13]; and, as if for the purpose of removing all such groundless speculations, Aaron was commanded to put a sample of it in a pot--a golden pot (Heb 9:4) --to be laid before the Testimony, to be kept for future generations, that they might see the bread on which the Lord fed their fathers in the wilderness. But we have the bread of which that was merely typical (1Co 10:3; Joh 6:32).

JFB.