16 And it will come about, when your numbers are increased in the land, in those days, says the Lord, that they will no longer say, The ark of the agreement of the Lord: it will not come into their minds, they will not have any memory of it, or be conscious of the loss of it, and it will not be made again. 17 At that time Jerusalem will be named the seat of the Lord's kingdom; and all the nations will come together to it, to the name of the Lord, to Jerusalem: and no longer will their steps be guided by the purposes of their evil hearts. 18 In those days the family of Judah will go with the family of Israel, and they will come together out of the land of the north into the land which I gave for a heritage to your fathers.
Matthew Henry's Commentary on Jeremiah 3:16-18
Commentary on Jeremiah 3:12-20
(Read Jeremiah 3:12-20)
See God's readiness to pardon sin, and the blessings reserved for gospel times. These words were proclaimed toward the north; to Israel, the ten tribes, captive in Assyria. They are directed how to return. If we confess our sins, the Lord is faithful and just to forgive them. These promises are fully to come to pass in the bringing back the Jews in after-ages. God will graciously receive those that return to him; and by his grace, he takes them out from among the rest. The ark of the covenant was not found after the captivity. The whole of that dispensation was to be done away, which took place after the multitude of believers had been greatly increased by the conversion of the Gentiles, and of the Israelites scattered among them. A happy state of the church is foretold. He can teach all to call him Father; but without thorough change of heart and life, no man can be a child of God, and we have no security for not departing from Him.