- Moshe ben Maimon, Sefer ha-Mitzvot, §62
The 62nd prohibition is that we are forbidden to swear a shvu'at shav (a vain oath). The source of this commandment is God's statement (Exo. 20:7), "Do not take the name of YHVH your God in vain."
המצווה הס"ב האזהרה שהזהרנו על שבועת שוא והוא אמרו יתעלה : " לא תשא את שם ה '
אלהיך לשוא." (שמות כ, ז)
[A shvu'at shav is] when one swears that something is the opposite of what it actually is; or, that something exists, when in fact it cannot; or, one who swears in order to violate a mitzvah of the Torah. So too if one swears by an obvious and undisputed fact. For example, swearing to God that anything which is slaughtered will die. Behold, this is also taking the name of YHVH in vain.
והוא שישבע על מחייב המציאות שהוא בהפך ממה שהוא באמת , או על דבר מן הנמנעות
שהוא מצוי , או שישבע לבטל מצווה מן התורה . וכן אם נשבע על דבר ידוע שאין עליו
מחלוקת ולא ויכוח לשום אדם מן המלמדים , כגון שישבע בה' שכל הנשחט ימות - הרי גם זה
נשא שם ה' לשוא.
And the expression of the Mishnah: "What is a shvu'at shav? An oath which contradicts an obvious truth." One who transgresses this prohibition intentionally is punished by lashes. If done unintentionally, he is exempt [from even bringing a sacrifice], as with many other prohibitions, as explained above. And there (that is to say, in Shvu'ot), it is said, "This is the shvu'at shav (vain oath) for which one is lashed if done intentionally and exempt if done unintentionally. The details of this mitzvah are explained there.
ולשון המשנה: "איזו היא שבועת שוא ? נשבע לשנות את הידוע לאדם וגו '." והעובר על לאו
זה במזיד - לוקה, ובשגגה - פטור, כשאר חייבי לאווין , כמו שביארנו . ושם אמרו , כלומר בשבועות: "זו היא שבועת שוא שחייבין על זדונה מכות ועל שגגתה פטור", ושם נתבארו דיני
- Moshe ben Maimon, Mishneh Torah, Sefer Hafla'ah, Hilkhot Shvu'ot, Chapter 1.4-8
4 The first type is when a person took an oath concerning a known matter that was not true, e.g., he took an oath that a man was a woman, a woman was a man, that a marble pillar was gold, or concerning other similar factors.
הָאַחַת, שֶׁנִּשְׁבַּע עַל דָּבָר הַ יָּד וּעַ שְׁאֵ ינוּ כֵּ ן . כֵּ יצַד--כְּגוֹן שֶׁנִּשְׁבַּע עַל הָאִישׁ שְׁהוּא אִ שּׁ ה, וְעַל
הָאִשָּׁה שְׁהִ יא אִ ישׁ, וְעַל עַמּ וּד שֶׁלְּשַׁ יִשׁ שְׁה וּא שֶׁלְּ זָהָב; וְכֵן כָּל כַּ יּוֹצֶא בְּזֶה.
5 The second: that one takes an oath on a known matter concerning which no one has a doubt, e.g., one took an oath that the sky was the sky, that a stone is a stone, on two [objects] that they are two, and the like. Even though there is no doubt about the matter for a person of sound mind, one takes an oath to strengthen [the appreciation of] the matter.
הַשְּׁ נִיָּה, שֶׁנִּשְׁבַּע עַל דָּבָר יָדוּעַ שְׁאֵין בּוֹ סָפֵק לְאָדָם בָּעוֹלָם שְׁהוּא כֵּן . כְּגוֹן שֶׁ נִּשְׁבַּע עַל הַשָּׁ מַ יִם
שְׁה וּא שָׁמַ יִם, וְעַל הָאֶבֶ ן זוֹ שְׁהִ יא אֶבֶ ן, וְעַל שְׁ נַיִם שְׁהֶם שְׁ נַיִם; וְכֵן כָּל כַּיּוֹצֶא בְּזֶה, שֶׁזֶּה הַדָּבָר אֵ ין
בּוֹ סָפֵק לְאָדָם שָׁלֵם כְּדֵי לְצַדַּק הַדָּבָר בִּשְׁבוּעָה.
6 The third is one who takes an oath to nullify a mitzvah. What is implied? One took an oath not to wrap himself in tzitzit, not to put on tefilin, not to dwell in a sukkah throughout the holiday of Sukkot, not to eat matzah on Pesach night, that he would fast on Shabbat and the festivals, or concerning other analogous instances.
שְׁלִ ישִׁ ית, שֶׁנִּשְׁבַּע לְבַטַּל אֶת הַמִּצְ וָה. כֵּ יצַד--כְּגוֹן שֶׁנִּשְׁבַּע שֶׁלּ אֺ יִתְעַטַּף בְּצִיצִית , וְשֶׁלּ אֺ יִלְבּ שֺׁ
תְּפִלִּ ין, וְשֶׁלּ אֺ יֵשֵׁב בַּסֻּכָּה בְּחַג הַסֻּכּוֹת , וְל אֺ י אֺכַל מַצָּה בְּלֵילֵי הַפֶּסַח , אוֹ שֶׁיִּתְעַנֶּה בְּשַׁבָּתוֹת
וְיָמִים טוֹבִים; וְכֵן כָּל כַּיּוֹצֶא בְּזֶה.
7 The fourth - that one took an oath concerning a matter that he is unable to perform. What is implied? He took an oath that he would not sleep for three consecutive days and nights, he would not eat for seven consecutive days or concerning any analogous matter.
רְבִ יעִ ית, שֶׁנִּשְׁבַּע עַל דָּבָר שְׁאֵין בּוֹ כּוֹחַ לַעֲשׂוֹתוֹ . כֵּ יצַד--כְּגוֹן שֶׁ נִּשְׁבַּע שֶׁלּ אֺ יִישַׁ ן שְׁ לוֹשָׁה יָמִים
לַ יְלָה וְיוֹם רְצוּפִ ים, א וֹ שֶׁ לּ אֺ יִטְע םֺ כְּלוּם שִׁבְעַת יָמִים רְצוּפִים; וְכֵן כָּל כַּיּוֹצֶא בְּזֶה.
8 Whenever a person takes an oath in vain by taking one of these four types of oaths, he transgresses a negative commandment, as (Exo. 20:6; Deut. 5:10) states, "And you shall not take the name of YHVH your God for falsehood." If he [takes the oath] willfully, he is liable for lashes. If he does so inadvertently, he is exempt entirely.
כָּל הַנִּשְׁבָּע שְׁבוּעַת שָׁוְא מֵאַרְבַּע שְׁבוּעוֹת אֵלּוּ--עוֹבֵר בְּל אֺ תַעֲשֶׂה, שֶׁ נֶּאֱמָר "ל אֺ תִשָּׂא אֶת-שֵׁם-
ה' אֱל הֶֺ יךָ , לַשָּׁ וְא" ( שמות כ ,ו; דברים ה ,י): וְאִם הָ יָה מֵזִיד , ל וֹקֶה; וְאִם הָיָה שׁוֹגֵג , פָּטוּר
- Philo, The Decalogue, Ch. XXIX, §157
157 By the third commandment, He restrains people from taking oaths, and limits the objects for which one may swear, defining when and where it may be lawful, and who may swear, and how the swearer out to be disposed, both in his soul and body, and many other minute particulars, concerning those who keep their oaths, and the contrary.
- Philo, The Decalogue, Ch. XVII, §82-87
82 The next commandment is, "not to take the name of God in vain." Now the
principle on which this order or arrangement proceeds is very plain to those who are gifted with acute mental vision; for, the name is always subsequent in order to the subject of which it is the name, being like the shadow which follows the body.
83 Therefore, having previously spoken of the existence of God, and also of the honor to be paid to the everlasting God, he then, following the natural order of connection, proceeds to command what is becoming in respect of His name. For, the errors of men with respect to this point are manifold and various, and assume many different characters.
84 That Being which is the most beautiful, and the most beneficial to human life, and suitable to rational nature, swears not Himself, because truth on every point is so innate within Him that His bare word is accounted an oath.6F7 Next to not swearing at all, the second best thing is to keep one's oath; for, by the mere fact of swearing at all, the swearer shows that there is some suspicion of his not being trustworthy.
85 Therefore, let a man be dilatory and slow if there is any chance that by delay he may be able to avoid the necessity of taking an oath at all. But, if necessity compels him to swear, then he must consider with no superficial attention, every one of the subjects, or parts of the subject, before him. For, it is not a matter of slight importance, though from its frequency it is not regarded as it ought to be.
86 For an oath is the calling of God to give His testimony concerning the matters which are in doubt; and, it is a most impious thing to invoke God to be witness to a lie. Come now, if you please, and with your reason look into the mind of the man who is about to swear to a falsehood, and you will see that it is not tranquil, but full of disorder and confusion, accusing itself, and enduring all kinds of insolence and evil speaking.
87 For the conscience which dwells in, and never leaves the soul of each individual, not being accustomed to admit into itself any wicked thing, preserves its own nature always such as to hate evil, and to love virtue, being itself at the same time an accuser and a judge. Being roused as an accuser it blames, impeaches, and is hostile. And, again as a judge, it teaches, admonishes, and recommends the accused to change his ways, and if he be able to persuade him, he is with joy reconciled to him, but if he be not able to do so, then he wages an endless and implacable war against him, never quitting him neither by day, nor by night, but pricking him, and inflicting incurable wounds on him, until he destroys his miserable and accursed life.