An introduction to the subject, A person grabbed a piece of metal from someone and a witness says so. And the person says, "Yes I took it because it is mine". R. Aba said he can not take an oath because he is not disagreeing with the witness, and so he must give back the piece. Tosphot asks why is this different from a case where one is a guard of an object with a document, and there he is believed with an oath because he could have said it was stolen. Here too let him be believed because he could have said ''I did not take it'' and be believed with an oath.
In the subject of the bar of metal of R. Aba, Rav Shach suggests the reason the person that grabbed it is not believed because the oath that he would like to take is not the oath of a guard where the Torah believes an a oath. That means to say that there are claims that a person is not believed even with an oath. In certain cases the Torah believes an oath, but this is not one of them. This is different from the case in Bava Batra page 70a where person is a guard of an object with a document. [The person that gave him the object to guard has a document to that effect.] There the guard is believed that he gave back the object because he has a migo that he could have said the object was stolen and be believed with an oath, Rav Shach explains that the case of, "I gave it back to you " is a case where the guard is in fact is saying that the object was stolen because now that the owner is saying he never got back the object that is a case where the owner is trying to steal the object. Two questions. One is that if so, then the fact that the guard is saying "I gave it back" is a case of it being stolen, and that case in itself is a plea that the Torah believes with an oath. The Torah is not believing him because of a migo, but because that in itself is a plea that the Torah believes with an oath (and yet the gemaras says the guard is believed because of a migo that he could have said it was neenas) The other question is that if Rav Shach is right then the owner is trying to steal the amount of money the object is worth, not the actual object. That would seem to depend if "the the value of money is like money" which we only say in certain cases like kidushin or the amount of money that a Hebrew slave can be redeemed with.
I am being short here because there a a few answers to this question of Tospfot in Bava Batra 35a. Rav Shach is mainly coming to answer this question in the Rambam because other answers do not seem to work so well in the Rambam.
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In the subject of the bar of metal נסכא of ר' אבא, Here רב שך suggests the reason the person that grabbed it is not believed because the oath that he would like to take is not the oath of a guard where the תורה believes an a oath. That means to say that there are claims that a person is not believed even with an oath. In certain cases the Torah believes an oath, but this is not one of them. This is different from the case in בבא בתרא ע' ע''א where person is a guard of an object with a document. [The person that gave him the object to guard has a document to that effect.] There the guard is believed that he gave back the object because he has a מיגו that he could have said the object was נגנב and be believed with an oath, רב שך explains that the case of "I gave it back to you " is a case where the guard is saying that the object was stolen because now that the owner is saying he never got back the object that is a case where the owner is trying to steal the object. Two questions. One is that if so, then the fact that the guard is saying "I gave it back" is a case of it being stolen, And that case in itself is a plea that the תורה believes with an oath. The תורה is not believing him because of a מיגו, but because that in itself is a plea that the תורה believes with an oath (and yet the גמרא says the guard is believed because of a מיגו that he could have said it was נאנס). The other question is that if רב שך is right, then the owner is trying to גונב the amount of money the object is worth, not the actual object. That would seem to depend if "the the value of money is like money" שווה כסף ככסף which we only say in certain cases like קיושין or the amount of money that a עב עברי can be redeemed with.
I am being short here because there a a few answers to this question of תוספות in בבא בתרא ל''ה ע''אa. Here רב שך is mainly coming to answer this question in the רמב''ם because other answers do not seem to work so well in the רמב''ם.
An introduction to the subject, A person grabbed a piece of metal from someone and a witness says so. And the person says, "Yes I took it because it is mine". ר' אבא said he can not take an oath because he is not disagreeing with the witness and o he must give back the piece. תוספות asks why is this different from a case where one is a guard of an object with a document and there he is believed with an oath because he could have said it was stolen.
בנושא נסכא של ר' אבא, כאן רב שך מציע את הסיבה לכך שהאדם שתפס אותו אינו נאמן כי השבועה שהוא רוצה להישבע אינה שבועת שומר במקום שבו התורה מאמין שְׁבוּעָה. כלומר שיש טענות שלא מאמינים לאדם אפילו בשבועה. במקרים מסוימים התורה מאמינה בשבועה, אך זו אינה אחת מהן. זה שונה מהמקרה בבא בתרא ע' ע''א שאדם הוא שומר על חפץ עם מסמך. [לאדם שנתן לו את החפץ לשמירה יש מסמך על כך.] שם השומר נאמן שהוא החזיר את החפץ כי יש לו מיגו שיכול היה לומר שהחפץ נגנב ולהאמין עם שבועה, רב שך מסביר שהמקרה של "החזרתי לך" הוא מקרה שבו השומר אומר שהחפץ נגנב כי עכשיו כשהבעלים אומר שהוא לא החזיר את החפץ זה מקרה שבו הבעלים מנסה לגנוב את החפץ. שתי שאלות. האחת היא שאם כן, אז העובדה שהשומר אומר "החזרתי" היא מקרה של גניבה, והמקרה הזה כשלעצמו הוא טענה שהתורה מאמינה בשבועה. התורה לא מאמינה לו בגלל מיגו, אלא בגלל שזו כשלעצמה זו טענה שהתורה מאמינה בשבועה (ואף על פי כן הגמרא אומרת שהשומר מאמינים בגלל מיגו שיכול היה לומר שזה נאנס). השאלה הנוספת היא שאם רב שך צודק, אז הבעלים מנסה לגנוב את סכום הכסף ששווה החפץ, לא החפץ בפועל. נראה שזה תלוי אם "ערך הכסף הוא כמו כסף", שם שווה כסף ככסף אנו אומרים רק במקרים מסוימים כמו קידושין או כמות הכסף שאיתו ניתן לפדות עבד עברי. אני מקצר כאן כי יש כמה תשובות לשאלה זו של תוספות בבבא בתרא ל''ה ע''א. כאן רב שך בא בעיקר לענות על שאלה זו ברמב''ם כי נראה שתשובות אחרות לא כל כך עובדות ברמב''ם
הקדמה לנושא, אדם תפס חתיכת מתכת ממישהו ועד אומר כך. והאדם אומר, "כן לקחתי את זה כי זה שלי". ר' אבא אמר שאינו יכול להישבע כי אינו חולק על העד ועליו להחזיר את החתיכה. תוספות שואלים למה זה שונה ממקרה שבו שומר על חפץ עם מסמך ושם מאמינים לו בשבועה כי יכול היה לומר שהוא נגנב.
