But I say unto you, Swear not at all; neither by heaven; for it is God's throne:
Read Chapter 5
Augustine of Hippo
AD 430
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 ...
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 wellchastised 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...
But I say unto you, &c. Christ here explains and perfects the third precept of the Decalogue, which the Scribes and Pharisees had explained falsely. For, 1. they asserted that an oath became an oath, and was binding, if it were made by God, and called Him to witness, but not so if it were sworn by creatures. Christ here teaches the contrary. For in creatures the Creator is understood, for they were made by God, and all that they have and are is from God. For he who swears, calls God, who is the prime Verity, to witness his oath. He therefore who swears by a creature, either makes that creature a God, which is the sin of idolatry, or else it behoves to understand God the Creator in the oath.
2. The Scribes erred, who thought that by this precept perjury only was forbidden. On the contrary Christ here teaches that by it every oath is forbidden, all irreverence and abuse of the name of God.
But I say unto you, &c. From this passage, the Pelagians, as S. Augustine testifies (Epist89 , q5...
Swear not at all. We must not imagine that here are forbidden all oaths, where there is a just and necessary cause of calling God to witness. An oath on such an occasion is an act of justice and religion. Here are forbidden unnecessary oaths in common discourse, by which the sacred name of God, which never ought to be pronounced without reverence and respect, is so frequently and scandalously profaned. (Witham)
'Tis not forbidden to swear in truth, justice and judgment; to the honour of God, or our own or neighbours' just defence; but only to swear rashly, or profanely, in common discourse, and without necessity. (Challoner)
Next, to lead them farther away from swearing by God, He says, 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.
