When Jeremiah writes chapter 29, Nebuchadnezzar has already deported about 3,000 Jews back to Babylon (see 52:28) - including King Jeconiah (29:2). So now Jeremiah writes a letter to those exiles (29:1).
Evidently the false prophecies of Hananiah (see yesterday) were preached in Babylon too, by one Ahab and one Zedekiah (21; different than the more famous men of those names). The exiles believed them and had placed their hope in the remnant of resistors back in Jerusalem. But God through Jeremiah tells them, you’ve got it all wrong - they will perish (17-22), because they did not repent.
You, who were exiled, you think you are in the worse place. But in fact, God says, I have placed you exiles in the place of mercy, that you might repent. They are not the preserved remnant - you are.
So settle in for the long haul. This repentance will not be granted by Me
in a moment - it will take seventy years (10). Use this time to learn to walk as you always should have walked: by faith, in Me. Live by faith in my promises, that I do have plans for you, to prosper you and not for evil (11a). I am not a cosmic cruel kid in the sky with a magnifying glass, capriciously aiming searing heat at the ants, My people. Walk by faith, that I will give you a future and a hope (11b).When you walk by this faith, you will prayerfully build homes and households and a new civilization right where I have planted you (5-7). You will cry out to Me, looking for Me, and you will find me (13), and I will gather and restore you (14).
Note 2 Timothy 2:25 - from Whom does even our own repentance come from?