Behold. Figure of speech Asterismos.
by the sword. Some codices, with two early printed editions, add "at the hand of".
the king of Babylon. This is the first occurrence in Jeremiah.
Related Commentaries of Jeremiah 20:4
Jeremiah 20:4
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.