In the previous Halacha, we have explained the basic aspects of a Torah-prescribed oath which is by one swearing to another in Bet Din using the name of Hashem, as such, “I hereby swear in the name of Hashem, G-d of Israel, that I owe this individual such-and-such amount of money.” We have also explained that Bet Din goes to great lengths to threaten and warn the individual not to swear falsely, so much so that many people who come to take an oath in Bet Din eventually forego the money they had claimed so as not to swear, even truthfully.
Let us now discuss the term many people commonly use when speaking to their friends, “I swear to you”. Is this prohibited and do such expressions constitute real oaths.
The Rishonim disagree whether or not an oath which does not include Hashem’s name is binding according to Torah law, for instance, if one says, “I swear that I saw such-and-such” instead of saying “I swear in the name of Hashem”. All Poskim agree that even if one is not liable for lashes for a false oath which did not contain the name of Hashem, nevertheless, this does still constitute a Torah prohibition whether one swears falsely about a past occurrence, such as, “I swear that I saw such-and-such” or one swears about a future occurrence, such as, “I swear I will not do such-and-such”; in any event, this does have the halachic validity of an oath according to Torah law. Indeed, Maran Ha’Shulchan Aruch (Yoreh De’ah, Chapter 237) states: “If one says ‘I swear that I will do/not do such-and-such’, this is considered an oath even if one has not invoked the name of Hashem or a nickname of Hashem.”
Based on this, we can infer that the custom of many empty people or people who simply do not know any better to utter oaths every single day is a terrible thing unto itself and they bring evil upon themselves, for as a result of sins related to vows and oaths, one’s children die, G-d-forbid. Even if one is swearing truthfully, when one is accustomed to using such expressions of swearing on a constant basis, one will eventually certainly transgress the sin of swearing falsely. This is especially true regarding those who swear about the future, such as, “I swear that I will not speak to so-and-so anymore” in that they are even more susceptible to transgressing the prohibition of swearing falsely.
Several Poskim, including Hagaon Harav Eliezer Papo in his Peleh Yo’etz, write that it is not only forbidden to swear in Hebrew; rather, this prohibition applies to other languages as well. Thus, one must take care never to say “I swear to G-d” or any other language that implies an oath, whether with or without the name of Hashem, in any language.
Similarly, those who swear by their father’s or brother’s life and the like, besides for the prohibition of swearing falsely, this also constitutes a lack of respect to these individuals by whom one swears constantly. The commentaries explain the verse, “For Hashem shall not cleanse one who bears his name in vain” to mean that Hashem will not cleanse even one who bears “his name”, i.e. one who swears by one’s own name falsely.
Summary: Those who constantly tell their friends “I swear to you” are unnecessarily and foolishly setting themselves a dangerous trap of transgressing the grave prohibition of swearing falsely, for swearing in the manner, although one has not mentioned the name of Hashem, constitutes an oath by Torah law and the punishment for this is very severe.