John Gill Commentary Judges 6:16

"And Jehovah said unto him, Surely I will be with thee, and thou shalt smite the Midianites as one man." — Judges 6:16 (ASV)

And the Lord said to him, surely I will be with you
The Targum is, "my Word shall be your help," which was sufficient to answer all objections taken from his meanness, unworthiness, and weakness.

and you shall smite the Midianites as one man ;
and as easily as if you had but one man to deal with, and the destruction be so entire and general that none shall be left.