My Catholic friend and I were chatting once and I said something along the lines of "I swear I'm not lying". She asked me to promise to her and not to swear since it's discouraged in her religion. I asked the reason and she just said that's what the church told her.
Is this claim true? Is swearing discouraged in Christianity? If so, why?
It may help to know that I was swearing to God that I was not lying. Is this allowed in Christianity, or is it appropriate only for important situations?
The key passages on this are:
James 5:12 (ESV):
But above all, my brothers, do not swear, either by heaven or by earth or by any other oath, but let your “yes” be yes and your “no” be no, so that you may not fall under condemnation.
and
Matthew 23:16-22 (ESV):
“Woe to you, blind guides, who say, ‘If anyone swears by the temple, it is nothing, but if anyone swears by the gold of the temple, he is bound by his oath.’ 17 You blind fools! For which is greater, the gold or the temple that has made the gold sacred? 18 And you say, ‘If anyone swears by the altar, it is nothing, but if anyone swears by the gift that is on the altar, he is bound by his oath.’ 19 You blind men! For which is greater, the gift or the altar that makes the gift sacred? 20 So whoever swears by the altar swears by it and by everything on it. 21 And whoever swears by the temple swears by it and by him who dwells in it. 22 And whoever swears by heaven swears by the throne of God and by him who sits upon it.
It seems that the issue here is that everything we say should be true. We should not need to claim a distinct truthfulness for a particular statement that contrasts to falsehoods in our normal dialogue. All of our statements should carry the same level of honesty and truthfulness.
In English, I don't think we really use the word "swear" in this way. Oftentimes it's just an expression.
The Pharisees were distinguishing between the object on which someone was swearing, when it shouldn't have mattered if there were any swearing at all.
So, if the person is sensitive to this particular phrase, you could simply explain that you are using the word as an idiom and not swearing by the temple or the gold of the temple or anything like that. Hopefully, the person can understand that.
It is actually quite dangerous to just accept church teaching without question. Knowing what without knowing why can lead to significant problems. This is where the question of Sola Scriptura and Church Authority collide. Acts 17:11 commends the Bereans for being more noble than the Thessalonians. The commendation was based on the fact that they didn't just accept what Paul taught, but "examined the Scriptures every day to see if what Paul said was true." If the Bereans were commended for this, we would do well to follow that pattern.
I've heard this too, but I don't know where it comes from and I've never read it in any of the Catechetical texts I use for teaching the faith. Certainly, there's a Biblical edict against swearing like that as @Narnian makes quite clear. But, there's another side to swearing. Which is making a vow.
Vows are very central to Catholicism, all of the Sacraments are essentially vows. All the covenants are vows. Everything in Catholicism is swearing, on your honor that you'll up hold your end of the bargain.
So, what's really to be avoided is an oath made in vain. Because that would be a violation of the 2nd commandment to not use the Lord's name in vain (or invoke His holy name for a pointless reason).
But, even rash vows have a place in Catholicism. Love itself, is a vow and to say, because it was entered in to on a whim, is not even vanity, it's closer to Godliness and it makes one freer as one binds themselves:
The revolt against vows has been carried in our day even to the extent of a revolt against the typical vow of marriage. It is most amusing to listen to the opponents of marriage on this subject. They appear to imagine that the ideal of constancy was a yoke mysteriously imposed on mankind by the devil, instead of being, as it is, a yoke consistently imposed by all lovers on themselves. They have invented a phrase, a phrase that is a black and white contradiction in two words—'free-love'—as if a lover ever had been, or ever could be, free. It is the nature of love to bind itself, and the institution of marriage merely paid the average man the compliment of taking him at his word.
So, if I ever find out where that teaching came from, I'll append it to here, but in general, making sacred oaths is about as taboo in Catholicism as wearing a Rosary around your neck (Read Manzoni's the Betrothed if you've ever had scruples about that).
There seems to be no clear understanding of James 5:12. John Wesley (Explanatory Notes on the Whole Bible) wrote:
"[The Apostle] does not forbid the taking a solemn oath before a magistrate. Let your yea be yea; and your nay, nay - Use no higher asseverations in common discourse; and let your word stand firm. Whatever ye say, take care to make it good."
And the Pulpit Commentary informs pulpiteers:
"James condemns only what is called profane swearing [profanity, and] hasty and frivolous oaths. Some commentators ..., some philosophers ..., some Fathers of the early Church, and some Christian sects ... interpret this command ... as an absolute condemnation of all kinds of swearing. [However,] upon solemn occasions oaths may be not only lawful, but sometimes also dutiful.... And Christian intelligence suggests that there can be nothing sinful in this, provided it be done only upon a solemn judicial occasion and in a reverent spirit. The words in the third commandment which are emphatic are evidently the words "in vain," it being assumed that there is a lawful use of the Divine Name."
On the other hand:
