Exodus 16:23

23. To-morrow is the rest of the holy sabbath This passage shows that the sabbath was known and observed among the Hebrews before the fourth commandment was given at Sinai . The division of the days into weeks seems to have been known among all the Shemitic nations from the earliest historic period, and this cannot fairly be accounted for except by a wide-spread tradition of the sacredness of the number seven, descending from the very origin of the race . Wilkinson shows that the seven-day division was known to the Egyptians, as proved by the seven days’ fete of Apis, the four times seven years of Osiris, the ten times seven days’ mourning for the dead, and the six times seven days of mortification imposed upon the priests . The Pythagoreans borrowed the week from Egypt, and the Roman world adopted it early in the second century . (Rawlinson’s Herod . , 2: 282 . ) It is probable that the week division and the sanctity of the sabbath were known to the Hebrews from their very origin as a people . We find that a week was the period of duration of the wedding feast in the time of Jacob . Genesis 29:27. Here, as in the creative week, God observes the sabbath as an example to man .