The fifth commandment: sermon on the fifth Sunday after Pentecost

By a Dominican Friar   |   19 June 2024

“You have heard that it was said to them of old: Thou shalt not kill …”

The words quoted by our Lord form the fifth of the ten commandments: “Thou shalt not kill.” And He says that our “justice” — that is, our obedience to this commandment and to all the others — must “abound more than” the justice “of the scribes and pharisees”. In other words, we are to keep the commandments against murder, adultery, and all the others not only by external obedience but also by conversion of heart. 

However, before our justice can abound more than that of the scribes and pharisees, it must first at least reach their level. So, let us look first at how we keep this commandment not to kill externally, before looking at the inward justice or holiness to which Christ calls us.

In the most obvious sense, “Thou shalt not kill” means that we must not take innocent human life. It doesn’t forbid all killing, for example, if it’s necessary to fight a just war, or if public authority needs to use capital punishment to prevent anarchy. But it does forbid us to extinguish the lives of the innocent, or even to be reckless of other people’s lives. So, some sins that are forbidden by God’s law are euthanasia, or abortion, or drunken driving. Then there are forms of fertility treatment that finish with unwanted human embryos being destroyed; that is one reason why IVF is forbidden by God’s law. Nor should we forget that contraceptive pills can act, among other things, to prevent a newly conceived human embryo from being implanted in the mother’s womb. All these things are contrary to the fifth commandment of the decalogue, “Thou shalt not kill”.

But this command also forbids us to harm the souls of others, as well as their bodies. Whenever my words or actions lead another person to sin, or confirm him in his bad choices, I am harming his soul, and committing what is called the sin of scandal. For example: someone tells me that he is planning to take revenge on a neighbour who has wronged him. If I say nothing, I am consenting to his action. But the bible says, “Vengeance is mine, says the Lord, I will repay.” Unless we are in a position of authority, like a high-court judge, it’s not our business to punish people for the wrongs that they do. Or if someone who is married but separated from his wife tells me that he is going to marry another woman, and I congratulate him, then I am encouraging him in wrongdoing. I am giving him scandal; wounding not his body but his soul. 

So much for external obedience to this commandment. But Jesus calls us to something higher. He wants to pluck out from our hearts not only sins but the roots of sin. One of these roots, and one that often leads us to wrong our neighbour, is the passion of anger. There is such a thing as righteous anger, but it is very rare, and among fallen men and women such as ourselves it is perhaps never found in a pure form. At any rate, we can be sure that if we ever deliberately welcome the emotion of anger into our hearts, we are committing at least a venial sin. That is why our Lord says, “Whoever is angry with his brother will be liable to the judgement.” Our venial sins are soon over and soon forgotten, but if we don’t repent of them they don’t go away, and at our judgement we may be horrified to discover that we have brought a mountain of venial sins with us into the next life. How can we avoid this? At the end of each day, say at least one Our Father sincerely, from your heart; kiss your crucifix; and ask your Father to forgive you as you forgive others the wrongs they have done you that day.

Finally, our Lord gives us one motive for avoiding anger that may surprise us. The Holy Mass is more powerful, when the members of the Church are at peace with each other. “If thou offer thy gift at the altar,” He says, “and there thou remember that thy brother hath anything against thee; leave there thine offering before the altar, and go first to be reconciled to thy brother: and then coming, thou shalt offer thy gift.” Just as a mother prefers to receive a gift from a happy child, than from a sulky or discontented one, so the Church’s gift becomes more acceptable to God whenever her members love and forgive each other from their hearts. May His Holy Spirit grant us to receive this power, and so “enter into the kingdom of heaven”.