Commentary for Kiddushin 54:10
אלא ע"י גלגול
why? Because the Divine Law said, [and if thou hast not gone aside to uncleanliness,] being under thy husband,<span class="x" onmousemove="('comment',' Ibid. 19.');"><sup>18</sup></span> which [condition] is absent!<span class="x" onmousemove="('comment',' For neither may live with her husband (viz., the arus or yabam) until the marriage ceremony is completed.');"><sup>19</sup></span>
Daf Shevui to Kiddushin
The husband cannot make his betrothed wife take an oath. But if he is making his married wife take an oath, he can at the same time make her take an oath that she did not have relations with another man while betrothed. This is the biblical proof of the technique of “extension of an oath.”
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