Jeremiah 20:4
For thus saith the LORD, Behold, I will make thee a terror to thyself, and to all thy friends: and they shall fall by the sword of their enemies, and thine eyes shall behold it: and I will give all Judah into the hand of the king of Babylon, and he shall carry them captive into Babylon, and shall slay them with the sword.
Jeremiah 20:4 belongs to the warning that Judah's persistent sin would bring punishment through Babylon. The nation would be handed over to the king of Babylon as the instrument of that judgment. Its people would be carried away captive to Babylon, and many would be killed. The prophet's opponents and their friends would live to witness the disaster coming upon them.
All Judah would be given into the hand of the Babylonian king, who would remove them to his own land and put them to death by military force. The man directly addressed would be made a source of dread to himself and to all his associates. He and his friends would watch with their own eyes as their companions fell by the sword of their enemies.