Albert Barnes Commentary Numbers 10:31

"And he said, Leave us not, I pray thee; forasmuch as thou knowest how we are to encamp in the wilderness, and thou shalt be to us instead of eyes." — Numbers 10:31 (ASV)

You may be to us instead of eyes - A proverbial expression still in use in the East. Hobab would indicate the spots where water, fuel, and pasture might be found, or warn them of the dangers from hurricanes, and point out localities infested by robbers.