And Moab was sore afraid— i.e. Balak the king, and the people of Moab; for they were ignorant of God's commands, prohibiting the Israelites to disturb the Moabites in their possessions. Thus was fulfilled what Moses foretold, Exodus 15:15.
Related Commentaries of Numbers 22:3
Numbers 22:3
3 And Moab was sore afraid of the people, because they were many: and Moab was distressed because of the children of Israel.