On the sixth day, they gathered twice as much food—two omers per person—and all the leaders of the congregation came and reported this to Moses.
22. And it came to pass on the sixth day. The violation of the Sabbath is not yet recounted, but only the stupidity or dense ignorance of their rulers is set forth, for although they had heard from the mouth of Moses that God would on that day give what would be sufficient for two days’ provision, still they marvel, and tell it to Moses...
We have here, 1. A plain intimation of the observing of a seventh day sabbath, not only before the giving of the law upon Mount Sinai, but before the bringing of Israel out of Egypt, and therefore, from the beginning, Gen 2:3.
Commenting on Exodus 16:22-31
And he said unto them, this is that which the Lord hath said,.... Which he had said to Moses privately, for as yet he had said it to none else: tomorrow is the rest of the holy sabbath unto the Lord; according to Jarchi, the rulers asked Moses what this day was, different from other days, that double the quantity should be gathered?