John Calvin Commentary Deuteronomy 5:30

"Go say to them, Return ye to your tents." — Deuteronomy 5:30 (ASV)

Go say to them. He more plainly adds God’s consent to the people’s prayer; this means that what they had asked was ratified by God’s decree; from this it follows that, if they refuse to obey Moses, they will not only be guilty of perversity and fickleness, but will also violate a divine decree.

I have previously shown why God honors the doctrines of the law with various titles, namely, so that the Israelites might more willingly submit to them. But, so that they would not think that what was commanded them was only to remain in force and to be observed for a short time, He expressly refers to the perpetuity of the Law; for this is the meaning of the words in which He declares that He will teach them what they were to do in the land that He would give them.