Numbers 22:3

[Moav] became terrified. The word denotes fear, as in “fear for yourselves.”

Moav detested. They detested their lives, similar to “I am disgusted with my life.” This is a shortened sentence.

And the Moabaee feared before the people greatly because they were many, and they were distressed in their life before the sons of Israel.

AND MOAB WAS SORE AFRAID OF THE PEOPLE. The meaning of this is [that Moab stood in great fear] because they [the Israelites] were many,. This can be interpreted as “although they were many,” in which case the reference would be to the Moabites, [the word ki meaning “although”]. The meaning of the verse would thus be: “And Moab was sore afraid of the Israelites although they [the Moabites] were many, Ramban, wishing to exclude this interpretation, for the reason cited in the text, explains that the word ki here means “because”; hence the pronoun hu — “they” [they were many] refers to the Israelites. for Moab was small among the nations; and it was not an ancient people, like the Canaanites, the Amorites and other [nations of the] sons of Noah. Therefore they [the Moabites] were greatly afraid of the people who outnumbered them exceedingly, for they were fruitful, and increased abundantly, and waxed greater than the Moabites. And they were furthermore overcome with dread because of the children of Israel, for they had heard of the great wonders that had happened to them and their fathers. Now Moab knew that Israel would not take their land from them, since they had sent to them [offering peace] just as they had sent to Sihon, [asking permission only to pass through their land], saying, until I shall pass over the Jordan into the Land which the Eternal our G-d giveth us. Or it is also possible that they had heard of G-d’s prohibition, when He said to the Israelites, Be not at enmity with Moab., Verse 9. Therefore they said to the elders of Midian: “Even though the Israelites will not capture our land, they will lick up because of their great numbers all that is round about us, as the ox licketh up the grass of the field, and they will capture all [the lands] that surround us, just as they did to the two Amorite kings, and they will make us servants to do taskwork.”

ויקץ מואב, the expression describes someone becoming fed up with life, similar to when Rivkah had said that she would become fed up with her life if Yaakov were to marry a Canaanite girl as had Esau his brother (Genesis 27,46)

ויגר מואב, the leaders of Moav who had not allowed the Israelites to traverse their territory as reported in Judges 11,17 were now afraid,

כי רב הוא, for the Israelites were numerically superior to them, not because they felt inferior in military tactics.

ויקץ מואב, “the man in the street” considered their lives as not worth living because of the impending invasion by the Israelites.