Let the children of Israel keep the sabbath, and celebrate it in their generations. It is an everlasting covenant

And the children of Israel shall keep the sabbath, to observe the sabbath throughout their generations it is an everlasting covenant.

and the sons of Israel have observed the sabbath; to keep the sabbath to their generations is a covenant age-during,

Why the children of Israel shall keep the sabbath, to observe the sabbath throughout their generations, for a perpetual covenant.

And the children of Israel are to keep the Sabbath holy, from generation to generation, by an eternal agreement.

Observabunt itaque filii Israel Sabbathum, observando ipsum in generationibus suis, pactum est perpetuum.

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.

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 all those Jewish shadows, rites, and ceremonies, fled away and disappeared:
for a perpetual covenant; just in the same sense as circumcision was, Genesis 17:13.

It was to be observed throughout their generations, in every age, for a perpetual covenant - This was to be one of the most lasting tokens of the covenant between God and Israel.