John Calvin Commentary Exodus 16:27

"And it came to pass on the seventh day, that there went out some of the people to gather, and they found none." — Exodus 16:27 (ASV)

And it came to pass. This is the second transgression: by going out on the seventh day, they violated its religious observance. This monstrous greediness arose because they did not believe the truth of what we just heard Moses say, for he had plainly declared to them that they would not find the manna.

They, therefore, accuse him of falsehood, refusing to believe anything but their own eyes.

Meanwhile, the obligation of the Sabbath was disregarded by them. Indeed, they sought to profane the day which God had hallowed, so that it should in no way differ from other days.

Therefore, God justly denounces them with great bitterness, for in addressing Moses, He indicts the obstinate wickedness of the whole people.

Assuredly, Moses was not among those who had refused to obey God’s laws. However, by this general charge, the multitude who had transgressed were more severely rebuked, and a greater obligation is laid on Moses to chastise the people, as part of the blame is transferred to him.

By the expression “How long?” God implies the intolerable nature of their perversity, because there is no end to their offenses. By thus provoking greater vengeance with new crimes, they prove themselves to be incorrigible.