Gather thee from all the nations - This must refer to a more extensive captivity than that which they suffered in Babylon.
The rejection of Israel and the desolation of the promised inheritance were not to be the end of God‘s dispensations. The closing words of the address therefore are words of comfort and promise. Compare marginal reference and Deuteronomy 4:29 ff; 1 Kings 8:46-50.
The chastisements of God would lead the nation to repent, and thereupon God would again bless them.
Deuteronomy 30:3
Will turn thy captivity - Will change or put an end to thy state of captivity or distress (compare Psalm 14:7; Psalm 85:2; Jeremiah 30:18). The rendering of the Greek version is significant; “the Lord will heal thy sins.”
The promises of this and the following verses had no doubt their partial fulfillment in the days of the Judges; but the fact that various important features are repeated in Jeremiah 32:37 ff, and in Ezekiel 11:19 ff, Ezekiel 34:13 ff, Ezekiel 36:24 ff, shows us that none of these was regarded as exhausting the promises. In full analogy with the scheme of prophecy we may add that the return from the Babylonian captivity has not exhausted their depth. The New Testament takes up the strain (e. g. in John 11:51-52. Then shall there be “one fold and one shepherd” John 10:16. But whether the general conversion of the Jews shall be accompanied with any national restoration, any recovery of their ancient prerogatives as the chosen people; and further, whether there shall be any local replacement of them in the land of their fathers, may be regarded as of “the secret things” which belong unto God Deuteronomy 29:29; and so indeed our Lord Himself teaches us Acts 1:6-7.
Deuteronomy 30:6
Circumcise thine heart - Compare Deuteronomy 10:16 note; Jeremiah 32:39; Ezra 11:19.