In His famous Sermon on the Mount, Christ internalizes the law. He shows how sinful actions stem from sinful attitudes. Therefore, it is not just our actions that consummate the breaking of God’s commandments, but our attitudes as well. 

In the verse you’ve cited, Jesus is explaining how murder—the breaking of the sixth commandment—stems from anger. Thus, our Lord extends the sixth commandment beyond “Thou shalt not kill,” which He cites in verse 21, to include “Thou shalt not be angry with your brother without a cause,” which He commands in verse 22. 

Notice, all anger is not causeless. There are occasions when one’s anger may have a legitimate cause. Jesus got angry (Mark 3:5; John 2:13-16), but never sinned (2 Corinthians 5:21; 1 Peter 2:22; Hebrews 4:15). Likewise, Christians are admonished “to be angry and sin not” (Ephesians 4:26). 

In Matthew 5:22, Christ is prohibiting illegitimate anger, which leads to illegitimate actions. Furthermore, He is explaining how escalating anger increasingly imperils the soul. He pinpoints three intensifying degrees of anger, each of which progressively endangers our immortal souls. 

The first is causeless anger; that is, being angry with your “brother without a cause.” Have you ever caught yourself in an angry argument with your spouse, despite the fact that neither of you can remember how the argument got started or what it’s about? This is a telltale sign that something is wrong in your hearts and home. It’s much more than a simple disagreement, it’s symptomatic of a far more deep-seated problem. 

Many people today are angry all the time. They walk around mad looking for someone to vent their anger on. Although they attempt to justify their tirades by another driver’s failure to turn on his blinker light or some cashier’s shortchanging them a nickel, there is really no justification for them coming unglued every time someone fails to perform perfectly in their presence.  

Once your temper becomes uncontrollable, venting itself on one undeserving victim after another, you’re well on your way to the eternal ruination of your soul. As Jesus put it, you are seriously “in danger of the judgment.” 

Following the step of causeless anger, the next step taken toward eternal ruination is the step of self-exaltation. The word “Raca” was Aramaic and meant “empty one.” To refer to someone in so demeaning a way was to reduce them to insignificance and to elevate yourself to superiority. In other words, your anger has skyrocketed to the place where you no longer see anyone but yourself as being significant. 

Once you start viewing others as your inferiors and start becoming infuriated at them for not agreeing with you or catering to you, you are “in danger of the council.” The council Jesus is referring to is the Sanhedrin, which was the Supreme Court of the Jews in the days of Jesus. In our day, we would not say that such escalated anger puts us in danger of the council, but in danger of running afoul of the law. Truly, once we’ve adopted such a superior attitude toward others we become far more likely to commit crimes against their person or property.    

The final degree of soul imperiling anger that Jesus points us to is the pinnacle of totally disregarding the sanctity of human life. The word Jesus uses for “fool” in this verse meant more than mental dullness; it meant moral worthlessness. It was not just the demeaning of a man’s mind, but also of his heart and soul. Thus, to call one a “fool” was to believe that they were deserving of death and that their death would prove to be of no consequence. Obviously, when anger escalates to this point it spawns murderous intent in the heart and leaves one with no qualms about taking the life of another. 

The word “hell” comes from the Greek word “Gehenna.” “Gehenna” means “the Valley of Hinnom,” which was a valley south of Jerusalem where continually burning fire consumed the city’s refuse. Along with the city’s refuse, the corpses of executed criminals (murderers) were also burned at Gehenna. 

For someone to nurse their anger to the point where they developed a total disregard for the sanctity of human life was for them to “be in danger” of having their corpse tossed upon the continually burning fire of Gehenna. Even worse than the danger of Gehanna’s fire, however, was the “danger of hell fire.” Jesus is warning those with murder in their hearts that they are not only in danger of suffering capital punishment at the hands of man, but also eternal punishment at the hands of God.