Jamieson, Fausset and Brown on Genesis 2:3

3. blessed and sanctified the seventh day--a peculiar distinction put upon it above the other six days, and showing it was devoted to sacred purposes. The institution of the Sabbath is as old as creation, giving rise to that weekly division of time which prevailed in the earliest ages. It is a wise and beneficent law, affording that regular interval of rest which the physical nature of man and the animals employed in his service requires, and the neglect of which brings both to premature decay. Moreover, it secures an appointed season for religious worship, and if it was necessary in a state of primeval innocence, how much more so now, when mankind has a strong tendency to forget God and His claims?