The kingdom of Ammon lay to the east of Israel, beyond the Jordan River. It formed the eastern border with the territories that were given to the tribes of Gad and Reuben under Moses (Deuteronomy 3:12–17). The people of Ammon have a long history in Scripture. Like Moab, they were descendants of Lot after his daughters committed incest with him (Genesis 19:30–38). The Lord had instructed Israel not to attack Ammon as they journeyed to Canaan (Deuteronomy 2:16–23). However, Ammon’s relationship with Israel was not a friendly one. In the days of the Judges there was intermittent war between Ammon and Israel (Judges 11:4–33), which continued in Saul’s day (1 Samuel 11:1–11 and on into David’s reign (2 Samuel 10:1–19).1
After Assyria invaded northern Israel in 734 BC, the Ammonites took over part of Gad. They were subject to Assyria, but gained some independence when Assyria collapsed at the hands of the Babylonians. After the battle of Carchemish, Ammon had to submit to Babylon. As a vassal of Babylon, Ammon helped Nebuchadnezzar when Jehoiakim rebelled in 597 BC (2 Kings 24:2).2 However, Ammon was part of the meeting in Jerusalem that tried to plot rebellion against Babylon (Jeremiah 27:3). They showed their disloyalty to Babylon in 589 BC (Ezekiel 21:18–32), and her king, Baalis, played a role in the assassination of Gedaliah whom Babylon had made governor of Judah (Jeremiah 40:13–41:15). Nebuchadnezzar dealt with this rebellion by invading Ammon, Moab and Judah in 582 BC (Jeremiah 52:30). Ammon was so weakened that it fell to Arab invasion and by the middle of the sixth century it no longer existed as a nation.3
The most likely background to Jeremiah’s oracle against Ammon is the meeting in Jerusalem in 594 BC to plot against Babylon.4
1 Sur les enfants d'Ammon.Ainsi parle l'Eternel: Israël n'a-t-il point de fils? N'a-t-il point d'héritier? Pourquoi Malcom possède-t-il Gad, Et son peuple habite-t-il ses villes?