Jerusalem falling...
Verse 1-5
The final assault against Jerusalem had begun. God sent Jeremiah back to Zedekiah with a message to affirm His earlier pronouncement. Lord was giving the city to Babylon and Babylon was going to burn it to the ground. Jeremiah goes on to prophesy that Zedekiah would be taken captive and not killed. When Zedekiah did die is would be in peace, not by the sword. He would be lamented.
Verse 6-7
The war was down to Babylon against Jerusalem, Lachish, and Azekah. All the other fortified cities had fallen.
Verse 8-22
So, by Hebrew law, people could sell themselves into slavery; however, they were to be set free after six years, similar to returning the land to the original owners every seven years. And just like the land laws, people were not honoring the command to release their slaves. So, apparently, Zedekiah chose this law to enforce to try and earn the favor of the Lord. It's not clear why he picked this; but I would venture a guess that it probably had the least impact on him personally, since he would have palace staff and slaves that were not Hebrews- so he didn't have to release them.
The way Zedekiah managed this initiative was to make a covenant with the people to do release their male and female slaves. Covenant. Not just a law or a promise or a command. A covenant. That is a sacred agreement before the Lord. A bigger commitment by several magnitudes. So...it would be wise to follow through. And they did. They all let their slaves go.
The Ryrie Study Bible says that follow this covenant action, the siege lightened because Babylon had an advancing Egyptian army to deal with and the two-front war left them a bit distracted.
The previous slave owners took this event as a resolution to their siege crisis. Then instead of seeing a cause and affect from obeying God's law and getting something positive; they just focused on the positive and not what may have caused it. With the crisis averted (in their minds) they now felt free to force their freed slaves back into slavery. Which was illegal and antithetical to the ways of the Lord.
Starting in verse 12, the lord speaks to Jeremiah about this most unfortunate series of choices by the officials and Jewish slave owners. God reviews the history of the statute. He brought them out of slavery. He freely relieved all of them from the bondage of the Pharaoh and the Egyptian people. Then He reviewed the law--free your brother in the seventh year of their service. They have failed to obey this command.
And then He points out that they finally did the right thing and obeyed Him. They also made a covenant about this issue, making it a promise to Him and in His name. Not just a law or governmental command, but a covenant. Which means that when they captured their former servants and enslaved them, they profaned the name of the Lord.
Then the Lord proclaims a judgement on them. Because they disobeyed, He is releasing them.
“Therefore, thus says the Lord: You have not obeyed me by proclaiming liberty, every one to his brother and to his neighbor; behold, I proclaim to you liberty to the sword, to pestilence, and to famine, declares the Lord. I will make you a horror to all the kingdoms of the earth. Jeremiah 34:17
We live under a common grace that is easily taken for granted, forgotten, or maybe misunderstood entirely. Within that common grace, much evil is restrained, granting us all much freedom of which we aren't even really aware. Having that restraint of evil lift, having common grace cancelled, is a horrific proposition- but well earned by making such a fundamental commitment to the Lord and re-offending.
They made a covenant by the traditional ceremony of passing through a calf that had been bisected. Now, all of those who did that and re-offended the law were to be handed over to the enemy and the bird who eat their carcasses. He closes out the chapter by informing them that the pause in the siege they were enjoying was now over and Jerusalem, Zedekiah, and the Hebrew people would be handed over to Babylon. Jerusalem would be burned, the people taken captive, and the land would face desolation without inhabitants.