Exodus 16:28

How long refuse ye? In speaking to Moses personally, God addresses the nation as a whole and its disobedient individuals in particular. This is evident from the use in the Hebrew of the plural form of the verb “refuse.” There had already been one act of disobedience the day the manna was first given (v. 20), but now one of a more serious nature occurred. God, addressing them as Judge, asks them to face the question of when He might expect sinful conduct such as this to end, and when they would learn that they could gain nothing by disobedience. The later history of Israel shows clearly how “long” it would take them to learn this important lesson. God’s question, “How long,” etc., implies that they had for a considerable time been doing this very thing — breaking the Sabbath, in full knowledge of the fact that they were doing what was wrong (see on vs. 25,27).