Therefore the people of Israel shall keep the Sabbath, observing the Sabbath throughout their generations, as a covenant forever.
The sabbath is the hem and hedge of the whole law: where no conscience is made of it, farewell both godliness and honesty. God repeats it here with jealous care because the urgency of tabernacle-work might tempt them to break it, but even sacred work must yield to sabbath rest.
AI summary
Commenting on Exodus 31:12-18
Wherefore the children of Israel shall keep the sabbath,.... On whom the sabbath of the seventh day was only enjoined, as well as that of the seventh and of the fiftieth years, being all ceremonial and shadowy: to observe the sabbath throughout their generations; so long as the Mosaic dispensation lasted, and their civil polity and church state continued, even until the Messiah came, when...
A perpetual covenant - Because it is a sign of this future rest and blessedness, therefore the religious observance of it must be perpetually kept up. The type must continue in force till the antitype come.