Deuteronomy 2:37

only unto the land of the children of Ammon thou camest not, nor unto any place of the river Jabbok, toward the east and north, nor unto the cities in the mountains, the mountainous district of Ammonitis, nor unto whatsoever the Lord, our God, forbade us. Note that the Lord spared the Edomites, the Moabites, and the Ammonites, nations related to Israel, since He wanted to give them time and opportunity for repentance. In the very midst of the unbelievers and His professed enemies the Lord has His elect, whom He intends to lead to repentance by the glorious manifestations of His kindness and mercy.