Don’t take lightly
For I tell you. (Matthew 5: 22)
And Jesus said to his disciples: For I tell you, unless your righteousness exceeds that of the scribes and Pharisees, you will never enter the kingdom of heaven. “You have heard that it was said to those of old, ‘You shall not murder; and whoever murders will be liable to judgment.’ But I say to you that everyone who is angry with his brother will be liable to judgment; whoever insults his brother will be liable to the council; and whoever says, ‘You fool!’ will be liable to the hell of fire. So if you are offering your gift at the altar and there remember that your brother has something against you, leave your gift there before the altar and go. First be reconciled to your brother, and then come and offer your gift. Come to terms quickly with your accuser while you are going with him to court, lest your accuser hand you over to the judge, and the judge to the guard, and you be put in prison. Truly, I say to you, you will never get out until you have paid the last penny. (Matthew 5: 20-26)
The justice Jesus speaks about is not a human justice, but one that helps each of us to attain holiness. We can become holy not only by avoiding serious sin, but also by paying attention to venial sins because they predispose us to mortal sin. Moreover, Jesus reminds us that we do not only kill others "by our hands", but also "by our words". For example, we kill others by ruining the reputation of someone we think has done something wrong to us. Hence, let us not take the Ten Commandments lightly.
