Adam Clarke on Ezekiel 21:23

To them that have sworn oaths - To Zedekiah and his ministers, who had bound themselves by the oath of the Lord to be faithful to the Chaldeans, and to pay them the promised tribute. The oaths may refer, farther, to the alliances formed with the Egyptians, Ammonites, and others. They will not believe that Nebuchadnezzar shall succeed against them, while they expect the powerful assistance of the Egyptians.