God calls His children to come home to Him. It doesn’t matter where we’ve been, what we’ve done, or how long we’ve been gone. His love will never fade and He’ll always take us back. Even “Faithless Judah” and “Apostate Israel” could repent of their sin and come home. 
That’s Jeremiah’s call from God. In Jeremiah 3:14 he pleads with God’s prodigal children, “Return, O faithless children, declares the LORD; for I am your master; I will take you, one from a city and two from a family, and I will bring you to Zion.” God promises to forgive them and to bring them home again to the place of blessing, safety and prosperity.
God’s call to wayward children goes out to all even though He knows most will never hear Him. The verses following this, from 3:14 to 3:18 contain some profound prophecies. I think Jensen is right when he suggests that the it’s not the immediate future in that’s in view. He says, “The near future, in the foreknowledge of God, was to be very dark for Judah and Israel. True, there would be a time of restoration and rebuilding the temple, with revivals of heart. But on the whole, the generations of God’s people would be generations of stony hearts, eventually rejecting the Messiah, Christ. Beyond this, however, in the far, far future, there was a bright picture. God through Jeremiah portrays a touching scene of returners-in-heart when Judah and Israel, led by God (3:14), would walk together out of foreign lands back to the land of inheritance (3:18). The things of the old covenant would give way to glories of the new (3:16), proceeding from the throne of Jehovah in Jerusalem, to which even Gentiles would gather and around which there would be found no evil (3:17).”[1]
Why does God care about a people who cared not for Him? Why would He even want such “faithless children” back? Ryken answers that best. He writes, “Why does God do it? He does it for no reason at all except that he is a God of love. This is the inscrutable grace of God. He is gracious to the ungracious, faithful to the unfaithful, loving to the unloving. His call comes first. God issues the invitation to come back home before anything else happens, before we have made the slightest motion back toward him. This is the priority of the divine call in salvation.”[2] Jesus’ words in Matthew 11:28 take on new meaning when we realize He’s the God of Jeremiah still calling to us out of His love. He says, “come to me all of you who are weary and heavy laden and I will give you rest.”
[1] Irving L. Jensen, Jermiah and Lamentations, Everyman’s Bible Commentary (Chicago, IL: Moody Press, 1974), 27–28.
[2] Philip Graham Ryken, Jeremiah and Lamentations: From Sorrow to Hope, Preaching the Word (Wheaton, IL: Crossway Books, 2001), 55.