Jesus redefined murder: if murder was defined in the Torah as we do most of the time (taking another person’s life), Jesus boosted it. For Jesus, “murder” includes anger and labeling and damning others. But, this text cannot be applied simply as it is.
Why? To begin with, Jesus is responding to an interpretation of the law against a murder in which, evidently, judgment is restricted to manslaughter. Jesus wants that law deepened. Manslaughter, Jesus says, begins with anger and labeling and damning others. Why? Because it devalues other persons who are made as Eikons of God.

By the way, the internalization of murder is found in Judaism as well. Jesus isn’t proving his way as better than everything ever heard in Judaism, but showing just how his view of the Torah fits in his world. And, for him, the internal state is the seat of morality.
In the place of murder — anger, labeling, damning — Jesus sets the stakes higher: pursue reconciliation. Unlike Cain who murdered his brother, Jesus advocates reconciliation with the brother — perhaps like Joseph.
And this demand not to have anger needs to be seasoned a bit with Jesus’ rather demonstrative and “angry” language in Matthew 23, where Jesus inveighs against the scribes and Pharisees for hypocrisy, or Herod for being a “fox” (Luke 13), or his regular diatribe with “this generation” (Matt 11). One thinks here of Eph 4:26 and Dale Allison’s commentary on the SoM has some nice citations at this point. Perhaps, it might be argued, that anger was not expressed on such occasions.
It is worth observing, at least for me, that Jesus loved to exaggerate: is this perhaps his way of arguing that anger is bad and that reconciliation is good, and that the best way to make this clear is to overstate it?
Anger, then, is a disposition of devaluing another person below who and what they are, and not simply an emotion. Justifiable anger co-exists, so it seems to me, with “not being angry” in Matt 5:21-26. But, anger (as Jesus here defines it) is to be overwhelmed by the pursuit of reconciliation.
Those who wish to follow Jesus must, then, consider this high summons of Jesus: pursue reconciliation for the seed-bed of murder lies in the angry heart. Our brief discussion here has involved us in explaining the meaning of “anger,” but the focus of the text is on the pursuit of reconciliation instead of letting anger run wild.
In the weekend services pastor Gene Appel gave each of us a little “plank” and he somehow connected this little plank with the log in the eye of Matt 7 and the plank that blinds us to those who are alone or whom we don’t like or those whom we don’t love, and he summoned us to write names or attitudes on the plank and then snap them as we committed ourselves to reconciling and loving others.
The sound of snapping planks is the sound of reconciliation. It is a sweet sound.