Exodus 16:22

Twice as much. On the sixth day another miracle occurred. It had already been revealed to Moses that the people were to gather twice as much on Friday as on other days (v. 5), and they were to gather twice as much. But nothing had as yet been revealed concerning its miraculous preservation, nor as to the fact that none would fall on the Sabbath. By gathering a double amount Friday morning the people had complied with instructions thus far given. But experience during the week had shown that any left over would spoil before morning (v. 20). This problem the tribal leaders now brought before Moses. Apparently, God delayed specific instructions concerning the Sabbath until this very time, since they had not been necessary earlier in the week.