For in ordinary conversation what needful or reasonable occasion can intervene of violating this command? If there come under discourse a matter of reason, which is evidently true and certain, then what need can there be of an oath to affirm it, it sufficing to expose it to light, or to propose the evidences for it? If an obscure or doubtful point come to be debated, it will not bear an oath; it will be a strange madness to dare, a great folly to hope the persuading it thereby. What were more ridiculous than to swear the truth of a demonstrable theorem? What more vain than so to assert a disputable problem: oaths (like wagers) are in such cases no arguments, except silliness in the users of them.
If a matter of history be started, then if a man be taken for honest, his word will pass for attestation without further assurance; but if his veracity or probity be doubted, his oath will not be relied on, especially when he doth obtrude it. For it was no less truly than acutely said by the old poet, Ουκ ανδρος ορκοι πιστις, αλλ’ ορκων ανηρ, “The man doth not get credit from an oath, but an oath from the man.” And a greater author, “An oath,” saith St. Chrysostom, “doth not make a man credible; but the testimony of his life, and the exactness of his conversation, and a good repute. Many often have burst with swearing, and persuaded no man; others only nodding have deserved more belief than those who swore so mightily.” Wherefore oaths, as they are frivolous coming from a person of little worth or conscience, so they are superfluous in the mouth of an honest and worthy person; yea, as they do not increase the credit of the former, so they may impair that of the latter.
“A good man,” as Socrates did say, “should apparently so demean himself, that his word may be deemed more credible than an oath;” the constant tenour of his practice vouching for it, and giving it such weight, that no asseveration can further corroborate it.
He should τοις εργοις ευορκειν, “swear by his good deeds,” and exhibit βιον αξιοπιστον, “a life deserving belief,” as Clemens Alex. saith: so that no man should desire more from him than his bare assertion; but willingly should yield him the privilege which the Athenians granted to Xenocrates, that he should testify without swearing.
He should be like the Essenes, of whom Josephus saith, that everything spoken by them was more valid than an oath; whence they declined swearing.
He should so much confide in his own veracity and fidelity, and so much stand upon them, that he should not deign to offer any pledge for them, implying them to want confirmation.
“He should,” as St. Jerome saith, “so love truth, that he should suppose himself to have sworn whatsoever he hath said;” and therefore should not be apt to heap another oath on his words.
Upon such accounts common reason directed even pagan wise men wholly to interdict swearing in ordinary conversation, or about petty matters, as an irrational and immoral practice, unworthy of sober and discreet persons. “Forbear swearing about any matter,” said Plato, cited by Clem. Alex. “Avoid swearing, if you can, wholly,” said Epictetus. “For money swear by no god, though you swear truly,” said Socrates. And divers the like precepts occur in other heathens; the mention whereof may well serve to strike shame into many loose and vain people bearing the name of Christians.
Indeed, for a true and real Christian, this practice doth especially in a far higher degree misbecome him, upon considerations peculiar to his high calling and holy profession.
Plutarch telleth us that among the Romans the flamen of Jupiter was not permitted to swear, of which law among other reasons he assigned this: “Because it is not handsome that he to whom divine and greatest things are entrusted should be distrusted about small matters.” The which reason may well be applied to excuse every Christian from it, who is a priest to the most High God, and hath the most celestial and important matters concredited to him; in comparison to which all other matters are very mean and inconsiderable. The dignity of his rank should render his word verbum honoris, passable without any further engagement. He hath opinions of things, he hath undertaken practices inconsistent with swearing. For he that firmly doth believe that God is ever present with him, and auditor and witness of all his discourse; he that is persuaded that a severe judgment shall pass on him, wherein he must give an account for every idle word which slippeth from him, and wherein, among other offenders, assuredly liars will be condemned to the burning lake; he that in a great Sacrament (once most solemnly taken, and frequently renewed) hath engaged and sworn, together with all other divine commandments, to observe those which most expressly do charge him to be exactly just, faithful, and veracious in all his words and deeds; who therefore should be ready to say with David, “I have sworn, and am steadfastly purposed to keep thy righteous judgments,” to him every word hath the force of an oath; every lie, every breach of promise, every violation of faith doth involve perjury: for him to swear is false heraldry, an impertinent accumulation of one oath upon another; he of all men should disdain to allow that his words are not perfectly credible, that his promise is not secure, without being assured by an oath.