Charles Ellicott Commentary Exodus 16:28

"And Jehovah said unto Moses, How long refuse ye to keep my commandments and my laws?" — Exodus 16:28 (ASV)

How long will you refuse to keep my commandments? The people had already broken one of the positive precepts with respect to the manna ; now they broke another—in the spirit, at any rate—since they would have gathered had they found anything to gather. Thus they provoked God a second time; yet He was so merciful, that He destroyed them not, but turned His anger away, and did not stir up all His wrath (Psalms 78:38). Apparently He made allowance for the ordinance being a new one, to which they were not yet accustomed.