'Enemy' in the Bible

Then the king of Moab took his eldest son, who was to reign in his place, and offered him [publicly] as a burnt offering [to Chemosh] on the [city] wall [horrifying everyone]. And there was great wrath against Israel, and Israel’s allies [Judah and Edom] withdrew from King Jehoram and returned to their own land.

The enemy broke through the city walls, and all the soldiers tried to escape. They left the city during the night. They went through the gate between the two walls that is near the king's garden. (The Babylonians were all around the city.) Then they headed for the Jordan Valley.