A.T. Robertson Commentary Matthew 10:28

"And be not afraid of them that kill the body, but are not able to kill the soul: but rather fear him who is able to destroy both soul and body in hell." — Matthew 10:28 (ASV)

Destroy both soul and body in hell (κα ψυχην κα σωμα απολεσα εν γεεννη). Note "soul" here of the eternal spirit, not just life in the body. "Destroy" here is not annihilation, but eternal punishment in Gehenna (the real hell) for which see on 5:22. Bruce thinks that the devil as the tempter is here meant, not God as the judge, but surely he is wrong. There is no more needed lesson today than the fear of God.