Afterward I will bring again - The Ammonites are supposed to have returned with the Moabites and Israelites, on permission given by the edict of Cyrus.
Albert Barnes
Notes on the Whole Bible
In 1 Maccabees 5:6,7, the Ammonites appear again as a powerful nation.
Matthew Henry
Concise Bible Commentary
Might often prevails against right among men, yet that might shall be controlled by the Almighty, who judges aright; and those will find themselves mistaken, who, like the Ammonites, think every thing their own on which they can lay their hands. The Lord will call men to account for every instance of dishonesty, especially to the destitute.