The Lord promises to bless Jerusalem with happy worship
“This is what the LORD Almighty says: “Just as I had determined to bring disaster upon you and showed no pity when your fathers angered me,” says the LORD Almighty, 15 “so now I have determined to do good again to Jerusalem and Judah. Do not be afraid. 16 These are the things you are to do: Speak the truth to each other, and render true and sound judgment in your courts; 17 do not plot evil against your neighbor, and do not love to swear falsely. I hate all this,” declares the LORD.
Jeremiah had heard the Lord's determination. The Lord had seen to it that Jerusalem was uprooted and torn down, demolished. What a disaster (Jeremiah 28:31)!
Couldn't God have shown pity last minute and relented? No. He could not have without denying his own holiness.
But now God is reaffirming his covenant of grace with Jerusalem and Judah. "Do not be afraid," he says. The wonder of God's good news! If God is gracious for the sake of the Messiah, people have no reason to fear.
So we have no reason to do anything at all? Hardly. "Speak to each other," God says. "Speak the truth to each other."
Make sure all your dealings with each other, particularly those pertaining to legal matters, are truthful. Don't promise nice things while plotting dirty things. Don't lie in court.
God's reason, bottom line? "I hate all these things." It is true today too. God hates and despises wickedness in every form. He especially hates harming others with lies.