21 “You have heard that it was said to the people long ago, ‘You shall not murder, and anyone who murders will be subject to judgment.’ 22 But I tell you that anyone who is angry with a brother or sister will be subject to judgment. Again, anyone who says to a brother or sister, ‘Raca,’ is answerable to the court. And anyone who says, ‘You fool!’ will be in danger of the fire of hell. “Therefore, if you are offering your gift at the altar and there remember that your brother or sister has something against you, 24 leave your gift there in front of the altar. First, go and be reconciled to them; then come and offer your gift.
Jesus never beat about the bush in confronting wrong thinking or wrong attitudes. He understood the fostering of these things lead people to a whole lot of trouble. In the sermon on the mount, he describes the danger of being angry with a brother or sister. A brother and sister in this context were not your blood relatives but those of the faith, and at that time it was the Jewish people.
This is still relevant to his church today. The primary factor that made the early church attractive to a nonbeliever was the love that was experienced among the believers for one another. Anger directed at each other is not attractive, it does not reflect the God we serve.
Jesus equates targeted anger at another person with the premeditated killing of another human being. Just because the action hasn’t happened, the thoughts and the spirit associated with this feeling are enough to make you guilty of the same penalty.
Being angry at a fellow believer and not dealing with it brings you into judgement, in the highest spiritual court in the realm (In those days the Sanhedrin) and the punishment is death. Not just any death, but one that is associated with burning in hell for eternity!
Therefore holiness for Christ is being related to his Spirit and not the wrong one. The scriptures teach us that mankind can not live by bread alone but every word that precedes from God’s mouth. (Deuteronomy 8:2-3 and Matthew 4:4)
Where do our thoughts come from, God’s mouth or another?
The New Testament teaches us that two main Spirits are influencing the people of this earth one of truth seasoned with grace (John 16:13) and one who is the Father of lies (John 8:44). We are called to listen to the Spirit of truth and put into practice the words of God.
Jesus instructs those of true Faith to put right a wrong, elsewhere the scripture tells us not to let the sun go down upon your wrath (Ephesians 4:26-27). Seize the moment and the opportunity to change your attitude to others and respond with love and not contempt.
Why is this needed? We already mentioned reflecting God to those who are outside his church. However right relationships go beyond reflecting God, they are founded on the belief that what you do onto others as if you are doing to yourself (Matthew 7:12) or even Jesus. Any attack against a fellow believer is a self-inflicting wound, but also an attack against our Lord Jesus (Matthew 25:40).
That said not all anger is wrong, God himself talks of his anger or Zeal directed towards wrongdoing or iniquity (Exodus 20:25-26). Billy Graham coined the phrase love the sinner hate the sin. We should not be angry at people, but the things that prevent people from being who God created them to be.