Moab would be destroyed and cut off from being a nation. Because of his trust in his works and in his treasures, he would be captured. His god Chemosh will go forth into exile with its priests and princes (Jer. 48:1-10).
Moab magnified himself against Jehovah. Israel was a derision to him. He was very proud—his loftiness, his pride, his arrogance, and the haughtiness of his heart were heard of by people. Jehovah would therefore bring to an end in Moab the one who offered up in high places and burned incense to his gods. Moab would become a derision and a terror to all who were around him (vv. 26-44; cf. Isa. 16:6-14).
Jehovah will turn again the captivity of Moab in the latter days (Jer. 48:47).
From this portion we can see that God is not only the God of Israel but also the God of the Gentiles. Such a people as the Moabites, whose source was incest and who were condemned by God, still received the compassion of God to produce Ruth to bring forth Christ into mankind and to have a remnant to be among the restored nations, who will be the spectators in the new heaven and new earth.
Jeremiah 49:1-6 concerns Jehovah's punishment and judgment upon the children of Ammon.
Ammon was also born of Lot through incest with his daughter, as Moab was. The nation of Ammon typifies the world of fleshly lust that fights against God's chosen people and misleads them into idolatry (Judg. 11:12; 1 Sam. 12:12a; 2 Chron. 20:10-11; Psa. 83:4-8; 1 Kings 11:5, 7).
Both Moab and Ammon are the world of lust. One is the fleshly world with religion to entangle God's people, and the other is the fleshly world that fights against God's people.