Fear him not; a necessary caution, for he was a great giant, Deuteronomy 3:11, likely to strike them with terror.
Related Commentaries of Numbers 21:34
Numbers 21:34
34 And the LORD said unto Moses, Fear him not: for I have delivered him into thy hand, and all his people, and his land; and thou shalt do to him as thou didst unto Sihon king of the Amorites, which dwelt at Heshbon.