16 "And this is what will happen: You will increase and prosper in the land. The time will come" - God's Decree! - "when no one will say any longer, 'Oh, for the good old days! Remember the Ark of the Covenant?' It won't even occur to anyone to say it - 'the good old days.' The so-called good old days of the Ark are gone for good.
Matthew Henry's Commentary on Jeremiah 3:16
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.