Commentary for Kiddushin 55:2
אשכחן בודאי ספק מנלן
it surely follows that we superimpose [an oath]. Now, we have thus learnt this of a positive claim; how do we know it of a case of doubt?<span class="x" onmousemove="('comment',' E.g., A and B are partners in a business; when they come to dissolve partnership, A cannot demand that B shall swear that he did not purloin anything from the business, in order to satisfy his doubts. If, however, B is bound to swear on account of another matter, he must swear on this too. Now, it cannot be argued that this too follows a fortiori from sotah, where the charge of adultery is likewise only doubtful. For the principal oath in connection with sotah is entirely due to doubt; hence the superimposed oath is likewise. But in money matters the principal oath is imposed for a positive claim only.');"><sup>3</sup></span>