One thing that is clear in Matthew 10:28 is that a distinction is made between two dimensions of life.

Human beings are both “body” and “soul”. We are made up of a physical, visible, tangible dimension that is apprehended by our six senses. But we also consist of an invisible, hidden, “covered up” dimension. Jesus describes this hidden dimension of the human condition with the word “secret”. The word is kruptos; it is the same word Paul used to speak about the hidden inner life of the Spirit when he wrote

Rather, a person is a Jew who is one inwardly (kruptos “in secret”), and real circumcision is a matter of the heart—it is spiritual and not literal. (Romans 2:29)

The same word is used in I Peter to describe the inner life, when Peter writes,

let your adornment be the inner self (kruptos “in secret”) with the lasting beauty of a gentle and quiet spirit. (I Peter 3:4)

What Jesus wants his followers to understand is that there are people who can destroy the outer life of the body but have no power over the inner (“secret”) life of the soul. They are not to be feared.

What we should fear is anyone who can destroy our inner life. Having our inner life destroyed is what causes us to be destroyed in gehenna.  Having our inner life destroyed is the cause of all the suffering we experience. We think we suffer because life does not turn out the way we want it to.  But gehenna is a place to which we go because we allow our inner life to be destroyed. We condemn ourselves to gehenna.

One of the other places Jesus uses the word gehenna is in Matthew 5:22 where he says,

if you say, ‘You fool,’ you will be liable to the gehenna of fire.

Allowing for the fact that Jesus often used exaggerated expressions, it seems unreasonably extreme to suggest that you will suffer an eternity of hell simply for calling your brother a “fool.” The Greek word here for fool is moros, from which we get our English word “moron.”  It is the same word Jesus used in Matthew 23:17 to describe the scribes and the Pharisees when he said, “You blind fools!”

So if calling someone “fool” is cause for eternal punishment, Jesus would seem to have condemned himself to hell, which is ridiculous. So, it is possible to use the word “fool” in reference to another person in a way that it is such an accurate description of reality that it is simply a statement of truth.

That is not how most of us use the word “fool”. When we speak pejoratively of  another person it is usually with a desire to hurt.  And when we spend our lives trying to hurt others, we  hurt ourselves first. To call another person “fool” is to damage myself.

The person I need to fear is myself. I am the only person who has the power to “destroy both soul and body in gehenna“. I need to fear that part of my being that chooses death. I need to fear that part of myself that chooses to neglect my inner life and fails to take seriously the important task of nurturing my soul.

If we follow this line of thought, we will see that verse 28 provides a key to the rest of this difficult passage.

Jesus is saying that the inner life is not to be taken lightly. There is great potential for me to inflict serious harm upon myself if I ignore my inner well-being.

Jesus understood that bad things are going to happen.  He knew his followers were going to be hunted down, persecuted, and in many cases killed.  He knew that families were going to be torn apart and that his followers would become social outcasts.  But most important of all, Jesus knew that there was an inner dimension in his disciples that was stronger and more real and more important than all of the terrible things that might ever happen to them. Jesus knew that his followers had an inner strength, an inner life that transcends the struggles and difficulties of life. And he knew that this inner dimension must be nourished in order to flourish.