Matthew 5:37

37. Yea, yea; Nay, nay That is, use in conversation only these simple affimatives and negatives, enforced by no violent adjurations.

Cometh of evil The oath arises from men’s want of conversational veracity, or from an undue excitement of feeling. If men were not false in their simple affirmations no oath would be needed. Hence it is well said the man is the surety of the oath, not the oath of the man. Hence it is only where there is much falsehood that the oaths are needed; so that lying and swearing are twin vices. The habit of oaths also cherishes excited and violent feeling. It is averse to that calm, self-reliant firmness which both Christianity and dignified character require, and which can depend on its own simple affirmation for all the demands of life.

Men are often excited to more violent passion by the very profanity which is produced by passion. Our own violent expression increases our own violent feeling and character. And thus, lying, swearing, and violence are associate vices.

That the oath before the magistrate is not prohibited is plain, for our Lord himself answered under the oath imposed upon him by Caiaphas. (Matthew 26:63-64.) As magistracy is instituted by God, so the invocation of his presence has the solemnity of worship, not the irreverence of profanity. The oath, then, is the tie of society and not its dissolution.

And it is to preserve the purity of the authoritative oath that the licentious oath is forbidden.

So also the solemn appeal to God made by the pious man has none of the irreverence of profanity, but, again, a prayer-like solemnity. So St. Paul, (Galatians 1:20:) “Behold, before God, I lie not;” and, (2 Corinthians 1:23:) “I call God for a record upon my soul.” (4.) Christian law of conciliation.

The Mosaic law laid down the rule of punishment by the magistrate, to inflict the evil upon the wrong doer, which the wrong doer had committed against a complainant. Exodus 21:22. It was life for life, eye for eye, tooth for tooth. This is, no doubt, for the magistrate, the abstract principle of retribution, which must ever be retained in criminal law. But the Jews introduced this principle of retaliation into private life. Each man became judge for himself when and how far it should be inflicted. Thereby the principle of revenge was cultivated, and all conciliation became dishonourable.

Christ enjoins here a different method of dealing with an assailant. Instead of resenting every affront, and retorting every blow aimed, to disarm him by skilful generosity. Our Saviour expresses the principle by symbolic specimens; that is, by strong external instances. But these outward acts are to be understood as mere symbols to express the internal disposition, and mere examples to illustrate the general rule.

Judgment must always be exercised as to when and in what individual cases these laws of conciliation will apply. Certainly they will not apply where it is clear that no conciliation will follow. Our Lord here prescribes a method for an end, which cannot be used where the end could not be attained, and where the method would only produce useless submission to increasing aggression. The law of self-defence then comes in, to be exercised either under the magistrate, or, if necessary, in our own persons.