Do not be afraid of those who kill the body but cannot kill the soul. Rather, be afraid of the One who can hand both soul and body over to destruction in Gehenna.
In this saying Jesus reminds the disciples that their fear should not be of temporary dangers or of people who can harm only the body. He says that true fear should be directed toward God, because only he has authority over both body and soul. The term “Gehenna” here represents the final judgment, which concerns the loss of the soul. Jesus calls them to remain faithful to God even if that faithfulness meets physical danger, because faith and eternal life have greater value than bodily safety.