These three Chapters are unified by their setting. It's the tenth year of Zedekiah, the eighteenth of Nebuchadnezzar, and the mighty Babylonian has Jerusalem under siege. Outside the walls, two smaller walled towns (Lachish and Azekah) are all that hold out; all of the other villages of Judah, and the farms and fields, have abandoned to the conquerers. Jeremiah, deeply unpopular with the king for his constant prophecies that the city is about to fall -- as if that weren't perfectly obvious to everyone -- is under custody in the royal palace.
Jeremiah 32 is labelled "Jeremiah Buys a Field" in the NIV, and lo and behold it really is about a real estate transaction. Jeremiah takes a break from doom-laden geopolitical predictions to prophesy that his uncle is going to come and offer him a deal on a field. About then, Jeremiah's uncle shows up and offers to sell him a field. The text goes into a fair amount of detail about the transaction, which is to the tune of 17 shekels of silver.
11 I took the deed of purchase—the sealed copy containing the terms and conditions, as well as the unsealed copy— 12 and I gave this deed to Baruch son of Neriah, the son of Mahseiah, in the presence of my cousin Hanamel and of the witnesses who had signed the deed and of all the Jews sitting in the courtyard of the guard.There is a point to all this, and it is spelled out in a subsequent conversation between Jeremiah and God. It is this: that although Judean property values are taking a real beating right now, with the invasion and the imminent sack of the capital, that God's long-term plan is to restore the kingdom. Jeremiah isn't crazy to buy land at a time like this; if he hangs on to that deed, he or his heirs will eventually have a field worth probably quite a bit more than 17 shekels, in a peaceful and prosperous new Judah.
Jeremiah 33 is a monolog by God, as told to Jeremiah, about the plan for restoration. A new theme is introduced here, in which God is essentially saying "OF COURSE there's going to be a restoration of Judah, because of my covenant with David!" That covenant, he says, is every bit as binding as the covenant between God and day, and between God and night.
Back in Jeremiah 11, God had told Jeremiah that the covenant was "broken" because of bad Israelite behavior. When I go back and look closely, though, he doesn't specify that he's renouncing his end of the bargain, just that he's going to punish the humans for renouncing their end of it.
Jeremiah 34 is a two-parter. In the first six verses, Jeremiah has some good news for Zedekiah for a change. Nebuchadanezzar isn't going to kill him, just take him to join the other exiles in Babylon. He will die peacefully, and be remembered fondly. It does not say whether this had an effect on Zedekiah's defense of Jerusalem.
Meanwhile -- in the second half of the chapter -- Jeremiah had passed on a decree from God that all Hebrews were to free all of their Hebrew slaves. Everyone agreed to this, but then some of the slaveholders reneged. It seems like it would be hard to re-enslave people, but it was probably made easier by everyone being confined in a small city under siege. God is very angry about this new disobedience, and makes a statement that sounds in the NIV a little bit like the dialogue of an action movie hero during the revenge scenes:
you have not proclaimed freedom to your own people. So I now proclaim ‘freedom’ for you, declares the Lord—‘freedom’ to fall by the sword, plague and famine. (34)Jerusalem will fall, Zedekiah will be exiled, and the re-enslavers are destined for particularly nasty ends.
Sidebar: it's interesting that this passage wasn't picked up on more (as far as I know) back when people argued about whether or not the Bible justified slavery. Context makes it hard to really use the Bible to argue for or against much of anything, I've been finding, but as an out-of-context one-liner it's about as powerful of an anti-slavery statement as they come.