John Gill Commentary Numbers 21:29

"Woe to thee, Moab! Thou art undone, O people of Chemosh: He hath given his sons as fugitives, And his daughters into captivity, Unto Sihon king of the Amorites." — Numbers 21:29 (ASV)

Woe to you, Moab! you are undone
The whole country ruined, or likely to be so:

O people of Chemosh ;
which was the name of their idol, who is called the abomination of the Moabites, (1 Kings 11:7) (See
Gill on Jeremiah 48:7):

he has given his sons that escaped ;
that is, the idol Chemosh had given his sons, the men of the country that worshipped him, who escaped the
sword of the Amorites, these,

and his daughters, into captivity unto Sihon king of the Amorites ;
who took captive what he slew not, or would do so, Chemosh their god not being able to preserve them, but
obliged to deliver them up: thus the composers of this song insult the god of the Moabites, as it was usual
for conquerors so to do; see (Isaiah 10:10Isaiah 10:11) (36:18-20) , though some think these are the
words of the Israelites, making their observations upon the above song, which ends at verse twenty eight, and
scoffing at the idol of the Moabites.