For historical background you can read the section of the post with 2 Kings 25 & 2 Chronicles 36:15-21
Jeremiah 39 should follow Jeremiah 34 chronologically; but as you know, this book is not chronological! As a reminder, Jeremiah 34 involved God's judgment on Zedekiah for his lack of leadership. He tried one last attempt to please God by freeing the slaves, but the people took them back again when they hoped Egypt would repel the attack of the Babylonians.
Babylon's foreign policy was to deport the rich and powerful and leave the poor people in charge of the land, making them grateful and loyal to Babylon.
God had promised that Jeremiah would be rescued from all trouble (1:8). This came true when the Babylonians freed him, protected him, and treated him as a wise seer.
Remember that Eed-Melech risked his own life to save Jeremiah's (38:7-13). Consequently, God protected Ebed-Melech from the Babylonians.
"Do not be afraid of them
For I am with you to deliver you,"
declares the LORD
I will let you in on a little secret: I used to be a "Little Miss Much Afraid," like the main character in the classic book, Hind's Feet on High Places. That is why this verse in Jeremiah was VERY dear to me for many years as God led me into situations where I was the one speaking truth when I did not want to be led there.
For many years, I did not like that position, but I have grown into it, just like Jeremiah. And I have learned to not be afraid. On the other side, I feel like God has blessed me for the courageous steps. He has rescued me from all trouble, protected me, and given me a new name: Boldly Beloved.
If you want to know about a new name God wants to give you, see this video: "Unleashing Your Imagination"
What are you afraid of right now? Talk to God about it.
If you have not already read it, Hind's Feet on High Places is an excellent book for all believers to read.
Lord, make us fearless by Your power and strength. We ask this in Jesus' name. Amen.