Shevuot 39
מסרבין בו לאכול
<br> urged to eat: our Mishnah [refers to the case where] he is not urged to eat; and the Baraitha [to the case where] he is urged to eat, and he says: 'I shall not eat, I shall not eat'; so that when he swears, he means: 'I swear I shall not eat'. R. Ashi said: Read [in the Baraitha]: 'I swear I shall not eat of thine'. If so, what need is there to state it? - I might have thought his tongue became twisted, therefore he teaches us [that it is a definite negative].
מתניתין בשאין מסרבין בו לאכול ברייתא במסרבין בו לאכול וקאמר לא אכילנא ולא אכילנא דכי קא משתבע הכי קאמר שבועה שלא אוכל
Our Rabbis taught: Mibta is an oath; issar is an oath. What is the binding force of issar? If you say that issar is an oath, he is liable; and if not, he is exempt. If you say that issar is an oath! But you have just said that issar is an oath? Abaye said: Thus he means: Mibta is an oath; issar is tacked on to an oath. What is the binding force of issar? If you say, that which is tacked on to an oath is like a properly expressed oath, he is liable; and if not, he is exempt. And how do we know that mibta is an oath? Is it not because it is written: If any one swear, pronouncing with his lips. Then issar also [should be counted an oath], for it is written: Every vow and every oath of a bond? Then again, how do we know that issar has the force of being tacked on to an oath? Is it not because it is written: Or bound he,' soul by a bond with an oath? Then mibta also [should have the force of being tacked on to an oath], for it is written: Whatsoever it be that a man shall pronounce with an oath. But, said Abaye: That mibta is an oath we deduce from this: And if she be married to a husband while her vows are upon her, or the utterance of her lips, wherewith she hath bound her soul: Now, oath is not mentioned; with what, then, did she bind herself? With mibta. Raba said: In reality, I can say to you, that which is tacked on to an oath is not like a properly expressed oath; and thus he [the Tanna] means: Mibta is an oath; issar is also an oath; and what is the binding force of issar? Scripture placed it between a vow and an oath [to teach us that] if he expressed it in the form of a vow, it is a vow; and if in the form of an oath, it is an oath. Where did [Scripture] place it [between a vow and an oath]? And if in her husband's house she vowed, or bound her soul by a bond with an oath. <br>
רב אשי אמר תני שבועה שאי אוכל לך אי הכי מאי למימרא מהו דתימא לישניה דאיתקילא ליה קמ"ל:
And they follow their own opinions, for it has been stated: That which is tacked on to an oath - Abaye said,it is like a properly expressed oath; and Raba said,it is not like a properly expressed oath.
ת"ר מבטא שבועה איסר שבועה איסור איסר אם אתה אומר איסר שבועה חייב ואם לאו פטור אם אתה אומר איסר שבועה והא אמרת איסר שבועה הוא
An objection was raised; [for it has been taught:] What is issar which is mentioned in the Torah? He who says: I take it upon me that I shall not eat meat, and that I shall not drink wine, as on the day that my father died, or, as on the day that So-and-So died, or, as on the day that Gedaliah, son of Ahikam, was killed, or, as on the day that I saw Jerusalem in its destruction; he is prohibited [from eating meat, etc.]; and Samuel said: only if he had already made a vow on that day. Now, it is well, according to Abaye, for just as that which is tacked on to a vow is a vow, so that which is tacked on to an oath is an oath;