Responsa for Shevuot 75:8
ורבי יוחנן דייק ממתניתין מדקאמר ר' מאיר שבועה שאין לכם בידי כללא הוי מכלל דולא לך פרטא הוי דאי סלקא דעתך ולא לך כללא הוה אדמשמע לן שבועה שאין לכם בידי נשמעינן שבועה לא לך ולא לך ולא לך כל שכן שבועה שאין לכם בידי
But Samuel says: [If so,] why mention that in which he agrees with him; let him mention that in which he disagrees with him.<span class="x" onmousemove="('comment',' When stating his view in the Baraitha, R. Judah should say, 'not thee' is a general (in which he disagrees with R. Meir, who holds it is a particular) ; and not 'and not thee' is a particular (with which R. Meir agrees) .');"><sup>9</sup></span> 'And R'Johanan argues from our Mishnah': Since R'Meir says:<span class="x" onmousemove="('comment',' The author of an anonymous statement in the Mishnah is generally R. Meir.');"><sup>10</sup></span>
Teshuvot Maharam
A. The testimony of the witnesses to the effect that B provided A with a surety, is convincing proof that A had given the money to B as a loan. Although a person will sometimes buy what by law belongs to him in order to avoid litigation, this principle applies only when the rightful owner is not in possession of the disputed property, while in our case B was in possession of the money. Moreover, even if there were no such witnesses, we would have put no credence in B's assertion that he provided A with a surety only because he acted "inside the line of justice." For the principle of Miggo — that we ought to believe B's present statement since, were he inclined to lie, he could have denied altogether having provided A with a surety — does not apply to this case, since we are thoroughly convinced that had B not owed the money to A, he would not have repaid part of it.
SOURCES: Cr. 166; Am II, 164.