Set thy face against the Ammonites - We have already seen, Ezekiel 21:19, etc., that when Nebuchadnezzar left Babylon he was in doubt whether he should besiege Riblath, the capital of the Ammonites, or Jerusalem, the capital of the Jews, first: and having used his divination. he was determined, by the result, to attack Jerusalem the first. He did so and the Ammonites, seeing the success of his arms, made friends with him, and exulted in the ruin of the Jews. God resents this, and predicts their downfall with that of Edom, Moab, and the Philistines. The fulfillment of this prediction is not noted in Scripture: but Josephus tells us, that about five years after the taking of Jerusalem, Nebuchadnezzar turned his arms against the Ammonites and Moabites, and afterwards against Egypt; and having subdued those nations, he returned to Babylon. Joseph. Antiq., 50 x., c. 2. Berosus states, as quoted by Josephus, contra App., that Nebuchadnezzar subdued Syria, Arabia, Phoenicia, and Egypt: and consequently, that he had brought under his dominion the Ammonites, Moabites, and Idumeans, who were included among the Philistines. See Calmet.

Son of man, set thy face against the Ammonites,.... Who were of the posterity of Lot, implacable enemies of the Jews; who hated their religion, and envied their wealth and happiness; against these the prophet is bid to "set his face"; to look that way where they lived, and to put on a frowning countenance, and a menacing aspect: "strengthen thy face", as the Septuagint and Arabic versions render it; look boldly at them:
and prophesy against them; deliver out the following prophecy concerning them.