Matthew 5:34

In the next place proceeding to mendacity, the minister of covetousness (of false swearing I am silent, since even swearing is not lawful )-is trade adapted for a servant of God? But, covetousness apart, what is the motive for acquiring? When the motive for acquiring ceases, there will be no necessity for trading.

Otherwise; They who live in the simplicity of the faith have not need to swear, with them ever, what is is, what is not is not; by this their life and their conversation are ever preserved in truth.

By the grace of gospel teaching, the law given by Moses acquired an advantage. The law prescribes that one must not swear falsely; but according to the gospel one must not swear at all. The Holy Spirit had seen fit to order this through Solomon when he said, “Do not accustom your mouth to oaths.” And again: “Even as a well-chastised servant is not deterred from envy, whoever swears and does business will not be purged from sin.” Therefore it is absolutely inappropriate for us to swear. What need is there for us to swear when we are not allowed to lie at all and our words must always be true and trustworthy, so much so that they may be taken as an oath? On this, the Lord not only forbids us to swear falsely but even to swear, lest we appear to tell the truth only when we swear and lest (while we should be truthful in our every word) we think it is all right to lie when we do not take an oath. For this is the purpose of an oath: Everyone who swears, swears to the fact what he is saying is true. Therefore the Lord does not want a gap between our oath and our ordinary speech. Even as there must be no faithlessness in an oath, in our words there must be no lie. For both false swearing and lying are punished with divine judgment, as the Scripture says: “The mouth that lies kills the soul.” So whoever speaks the truth swears, for it is written: “A faithful witness will not lie.”

"Again, ye have heard that it was said to them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths. But I say unto you, swear not at all."

Why did He go straightway not to theft, but to false witness, passing over that commandment? Because he that steals, doth upon occasion swear also; but he that knows not either swearing or speaking falsehood, much less will he choose to steal. So that by this He hath overthrown the other sin likewise: since falsehood comes of stealing.

But what means, "Thou shalt perform unto the Lord thine oaths?" It is this, "thou shalt be true in swearing." "But I say unto you, swear not at all."

Next, to lead them farther away from swearing by God, He saith, "Neither by Heaven, for it is God's throne, nor by the earth, for it is the footstool of His feet; nor by Jerusalem, for it is the city of the great King:" still speaking out of the prophetical writings, and signifying Himself not to be opposed to the ancients. This was because they had a custom of swearing by these objects, and He intimates this custom near the end of His Gospel.

But mark, I pray thee, on what ground He magnifies the elements; not from their own nature, but from God's relation to them, such as it had been in condescension declared. For because the tyranny of idolatry was great, that the elements might not be thought worthy of honor for their own sake, He hath assigned this cause, which we have mentioned, which again would pass on to the glory of God. For He neither said, "because Heaven is beautiful and great," nor, "because earth is profitable;" but "because the one is God's throne, the other His footstool;" on every side urging them on towards their Lord.

"Neither by thy head," saith He, "because thou canst not make one hair white or black."

Here again, not as wondering at man, hath He withdrawn him from swearing by his head (for so man himself would be worshipped), but as referring the glory to God, and signifying that thou art not master even of thyself, and of course therefore not of the oaths made by thy head. For if no one would give up his own child to another, much more will not God give up His own work to thee. For though it be thy head, yet is it the property of another; and so far from being master thereof, thou shalt not be able to do with it, no not the least thing of all. For He said not, "Thou canst not make one hair grow;" but, "Not so much as change its quality."

"But what," it may be said, "if any one should require an oath, and apply constraint?" Let the fear of God be more powerful than the constraint: since, if thou art to bring forward such excuses, thou wilt keep none of the things which are enjoined.

Yea, for first with respect to thy wife thou wilt say, "what if she be contentious and extravagant;" and then as to the right eye, "what if I love it, and am quite on fire?" and of the unchaste look, "what then, if I cannot help seeing?" and of our anger against a brother, "what if I be hasty, and not able to govern my tongue?" and in general, all His sayings thou mayest on this wise trample under foot. Yet surely with regard to human laws thou darest not in any case use this allegation, nor say, "what then if this or that be the case," but, willing or unwilling, thou receivest what is written.

And besides, thou wilt never have compulsion to undergo at all. For he that hath hearkened unto those former blessings, and hath framed himself to be such as Christ enjoined, will have no such constraint to endure from any, being held in reverence and veneration by all.

"But let your yea, be yea; and your nay, nay: for that which exceedeth these cometh of the evil one."

What is it then that "exceeds yea" and "nay"? it is the oath, not the perjury. For this latter is quite acknowledged, and no man needs to learn that it is of the evil one; and it is not an excess, but an opposite: whereas an excess means something more, and added over and above: which kind of thing swearing is.

"What then," saith one, "was it of the evil one? and if it was of the evil one, how was it a law?" Well, this same thing thou wilt say concerning the wife also; how is that now accounted adultery, which was before permitted?

What now may one reply to this? That the precepts then uttered had reference to the weakness of them who were receiving the laws; since also to be worshipped with the vapor of sacrifice is very unworthy of God, just as to lisp is unworthy of a philosopher. That kind of thing accordingly was now laid down to be adultery, and swearing to be of the evil one, now that the principles of virtue have advanced. But if these things had been, from the first, laws of the devil, they would not have attained to so great goodness. Yea, for had those not been forerunners in the first place, these which we now have would not have been so easily received. Do not thou then require their excellency now, when their use is past: but then, when the time was calling for them. Or rather, if thou wilt, even now: yea, for now also is their virtue shown: and most of all for the very cause, by reason of which we find fault with them. For their appearing such now, is the greatest commendation of them. For had they not brought us up well, and made us meet for the reception of the greater precepts, they would not have appeared such.

Therefore as the breast, when it hath fulfilled all its part, and is dismissing the child to the more manly diet, after that appears useless; and the parents who before thought it necessary for the babe, now abuse it with ten thousand mockeries (and many even not content with words of abuse, anoint it also with bitter drugs; that when their words have not power to remove the child's unseasonable propensity towards it, the real things may quench their longing): so also Christ saith, that they are of the evil one, not to indicate that the old law is of the devil, but in order that with most exceeding earnestness He might lead them away from their ancient poverty.

But if the old law had belonged to the devil, it would not have led people away from idolatry, but rather would have drawn them on and cast them into it; for this did the devil desire. But now we see the opposite effect produced by the old law. And indeed this very thing, the oath, was ordained of old for this cause, that they might not swear by the idols. For "ye shall swear," saith He, "by the true God." They were then no small advantages which the law effected, but rather very great. For that they came unto the "strong meat," was the work of its care.

"What then," it may be said, "is not swearing of the evil one?" Yes, indeed it is altogether of the evil one; that is, now, after so high a rule of self-restraint; but then not so.

"But how," one may say, "should the same thing become at one time good, at another time not good?" Nay, I say the very contrary: how could it help becoming good and not good, while all things are crying aloud, that they are so: the arts, the fruits of the earth, and all things else?

See it, for example, taking place first in our own kind. Thus, to be carried, in the earliest age of life, is good, but afterwards pernicious; to eat food that hath been softened in the mouth, in the first scene of our life, is good, but afterwards it is full of disgust; to be fed upon milk and to fly to the breast, is at first profitable and healthful, but tends afterwards to decay and harm. Seest thou how the same actions, by reason of the times, appear good, and again not so? Yea, and to wear the robe of a child is well as long as you are a boy, but contrariwise, when you are become a man, it is disgraceful. Wouldest thou learn of the contrary case too, how to the child again the things of the man are unsuited? Give the boy a man's robe, and great will be the laughter; and greater the danger, he being often upset in walking after that fashion. Allow him to handle public affairs, and to traffic, and sow, and reap, and great again will be the laughter.

Note how He exalts the elements of the world, not from their own nature, but from the respect which they have to God, so that there is opened no occasion of idolatry.

Or; of evil, that is, from their weakness to whom the Law permitted the use of an oath. Not that by this the old Law is signified to be from the Devil, but He leads us from the old imperfection to the new abundance.

(Versed 34 onwards) But I say to you, do not swear at all: neither by heaven, for it is the throne of God; nor by the earth, for it is his footstool; nor by Jerusalem, for it is the city of the great King. Nor should you swear by your head, because you cannot make a single hair white or black. Let your word be 'Yes, yes' or 'No, no'; anything more than this comes from evil. The Jews have always had this wicked habit of swearing by the elements, as the prophetic word often accuses them (Isaiah 65). Whoever swears, worships, or loves the one by whom they swear. In the law it is commanded that we do not swear, except by the Lord our God (Deut. VI and VII). The Jews, by swearing by angels, and by the city of Jerusalem, and by the temple, and by the elements, honored and worshipped creatures and earthly things with the honor and worship due to God. Finally, consider that here the Savior did not prohibit swearing by God, but by heaven, and earth, and Jerusalem, and by your own head. And this was granted in the law as if to little children, so that just as they would sacrifice animals to God and not to idols, they would be allowed to swear by God: not that they would do this rightly, but because it was better to offer this to God than to demons. However, evangelical truth does not require an oath, since every faithful statement is considered as if made under oath.

This was allowed under the Law, as to children; as they offered sacrifice to God, that they might not do it to idols, so they were permitted to swear by God; not that the thing was right, but that it were better done to God than to dæmons.

Lastly, consider that the Saviour does not here forbid to swear by God, but by the Heaven, the Earth, by Jerusalem, by a man's head. For this evil practice of swearing by the elements the Jews had always, and are thereof often accused in the prophetic writing's. For he who swears, shows either reverence or love for that by which he swears. Thus when the Jews swore by the Angels, by the city of Jerusalem, by the temple and the elements, they paid to the creature the honour and worship belonging to God; for it is commanded in the Law that we should not swear but by the Lord our God.

Therefore Evangelic verity does not admit an oath, since the whole discourse of the faithful is instead of an oath.

But it may be asked why, when it was said, But I say unto you, Swear not at all, it was added, neither by heaven, for it is God's throne, etc., up to neither by your head. I suppose it was for this reason, that the Jews did not think they were bound by the oath, if they had sworn by such things: and since they had heard it said, You shall perform unto the Lord your oath, they did not think an oath brought them under obligation to the Lord, if they swore by heaven, or earth, or by Jerusalem, or by their head; and this happened not from the fault of Him who gave the command, but because they did not rightly understand it. Hence the Lord teaches that there is nothing so worthless among the creatures of God, as that any one should think that he may swear falsely by it; since created things, from the highest down to the lowest, beginning with the throne of God and going down to a white or black hair, are ruled by divine providence. Neither by heaven, says He, for it is God's throne; nor by the earth, for it is His footstool: i.e., when you swear by heaven or the earth, do not imagine that your oath does not bring you under obligation to the Lord; for you are convicted of swearing by Him who has heaven for His throne, and the earth for His footstool. Neither by Jerusalem, for it is the city of the great King; a better expression than if He had said, My [city]; although, however, we understand Him to have meant this. And, because He is undoubtedly the Lord, the man who swears by Jerusalem is bound by his oath to the Lord. Neither shall you swear by your head. Now, what could any one suppose to belong more to himself than his own head? But how is it ours, when we have not the power of making one hair white or black? Hence, whoever should wish to swear even by his own head, is bound by his oath to God, who in an ineffable way keeps all things in His power, and is everywhere present. And here also all other things are understood, which could not of course be enumerated; just as that saying of the apostle we have mentioned, By your rejoicing, I die daily. And to show that he was bound by this oath to the Lord, he has added, which I have in Christ Jesus.

But yet (I make the remark for the sake of the carnal) we must not think that heaven is called God's throne, and the earth His footstool, because God has members placed in heaven and in earth, in some such way as we have when we sit down; but that seat means judgment. And since, in this organic whole of the universe, heaven has the greatest appearance, and earth the least—as if the divine power were more present where the beauty excels, but still were regulating the least degree of it in the most distant and in the lowest regions—He is said to sit in heaven, and to tread upon the earth. But spiritually the expression heaven means holy souls, and earth sinful ones: and since the spiritual man judges all things, yet he himself is judged of no man, he is suitably spoken of as the seat of God; but the sinner to whom it is said, Earth you are, and unto earth shall you return, because, in accordance with that justice which assigns what is suitable to men's deserts, he is placed among things that are lowest, and he who would not remain in the law is punished under the law, is suitably taken as His footstool.

(de Mendac. 15.) But what we could not understand by mere words, from the conduct of the saints we may gather in what sense should be understood what might easily be drawn the contrary way, unless explained by example. The Apostle has used oaths in his Epistles, and by this shows us how that ought to be taken, I say unto you, Swear not at all, namely, lest by allowing ourselves to swear at all we come to readiness in swearing, from readiness we come to a habit of swearing, and from a habit of swearing we fall into perjury. And so the Apostle is not found to have used an oath but only in writing, the greater thought and caution which that requires not allowing of slip of the tongue. Yet is the Lord's command so universal, Swear not at all, that He would seem to have forbidden it even in writing. But since it would be an impiety to accuse Paul of having violated this precept, especially in his Epistles, we must understand the word at all as implying that, as far as lays in your power, you should not make a practice of swearing, not aim at it as a good thing in which you should take delight.

(cont. Faust. xix. 23.) Therefore in his writings, as writing allows of greater circumspection, the Apostle is found to have used an oath in several places, that none might suppose that there is any direct sin in swearing what is true; but only that our weak hearts are better preserved from perjury by abstaining from all swearing whatever.

(Serm. in Mont. i. 17.) Or; It is added, By the Heaven, &c. because the Jews did not consider themselves bound when they swore by such things. As if He had said, When you swear by the Heaven and the Earth, think not that you do not owe your oath to the Lord your God, for you are proved to have sworn by Him whose throne the heaven is, and the earth His footstool; which is not meant as though God had such limbs set upon the heaven and the earth, after the manner of a man who is sitting; but that seat signifies God's judgment of us. And since in the whole extent of this universe it is the heaven that has the highest beauty, God is said to sit upon the heavens as showing divine power to be more excellent than the most surpassing show of beauty; and He is said to stand upon the earth, as putting to lowest use a lesser beauty. Spiritually by the heavens are denoted holy souls, by the earth the sinful, seeing He that is spiritual judgeth all things. (1 Cor. 2:15.) But to the sinner it is said, Earth thou art, and unto earth thou shalt return. (Gen. 3:19.) And he who would abide under a law, is put under a law, and therefore He adds, it is the footstool of His feet. Neither by Jerusalem, for it is the city of the Great King; this is better said than 'it is mine;' though it is understood to mean the same. And because He is also truly Lord, whoso swears by Jerusalem, owes his oath to the Lord. Neither by thy head. What could any think more entirely his own property than his own head? But how is it ours when we have not power to make one hair black or white? Whoso then swears by his own head also owes his vows to the Lord; and by this the rest may be understood.

For no man can swear often, but he must sometimes forswear himself; as he who has a custom of much speaking will sometimes speak foolishly.

Having forbidden swearing, He instructs us how we ought to speak, Let your speech be yea, yea; nay, nay. That is, to affirm any thing it is sufficient to say, 'It is so:' to deny, to say, 'It is not so.' Or, yea, yea; nay, nay, are therefore twice repeated, that what you affirm with the mouth you should prove in deed, and what you deny in word, you should not establish by your conduct.

(non occ.) The Lord has hitherto taught to abstain from injuring our neighbour, forbidding anger with murder, lust with adultery, and the putting away a wife with a bill of divorce. He now proceeds to teach to abstain from injury to God, forbidding not only perjury as an evil in itself, but even all oaths as the cause of evil, saying, Ye have heard it said by them of old, Thou shall not forswear thyself. It is written in Leviticus, Thou shalt not forswear thyself in my name; (c. 19:12.) and that they should not make gods of the creature, they are commanded to render to God their oaths, and not to swear by any creature, Render to the Lord thy oaths; that is, if you shall have occasion to swear, you shall swear by the Creator and not by the creature. As it is written in Deuteronomy, Thou shall fear the Lord thy God, and shall swear by his name. (c. 6:13.)