John Calvin on Deuteronomy 30:4-5

4. If any of thine be driven out. Since their dispersion into unknown countries might have altogether annihilated their hope of restoration, Moses anticipates this doubt, and teaches them that, although they might be driven out into the utmost regions of the earth, the infinite power of God sufficed to gather them from thence; as also it is said in Psalm 147:2,

“The Lord doth build up Jerusalem; he gathereth together the outcasts of Israel.”

With this intent, the adverb “from thence” is twice repeated, lest they should imagine that the distance of place would be any impediment to the fulfillment of what God had promised.

We have seen elsewhere that it was not without reason that their dwelling in the land of Canaan was magnified as a peculiar blessing, because it behooved that, until the time of Christ’s coming, the hope of an eternal inheritance should be cherished in their minds by an earthly and visible symbol.