There is some encouragement here in the series of verses in Matthew 10. It indicates that, if one really fears God, then there is no need to be fearful of others. Proverbs 29:25 very plainly tells us that, The fear of man is a snare. This is something by which we do not want to be entrapped.
I think it obvious, in the context of Matthew 10 and beginning with verse 27, that He is talking about fear in the sense of dread.The reason that we are not to fear men is because the worst that they can do cannot even begin to match the worst that God can do! The basis for this is what God is: omnipotent, omniscient, and in Him are the issues of life and death!