Reference for Shevuot 94:1

אי אמרת בשלמא אביו כי האי גוונא מיחייב איצטריך קרא למיפטר גבי יורשין אלא אי אמרת אביו כי האי גוונא נמי פטור קרא גבי יורשין למה לי

Now granted, if you say, that his father in such circumstances, would have been liable [to take an oath],<span class="x" onmousemove="('comment',' And since he could not take an oath, for he is not sure, he would have had to pay.');">¹</span> it is therefore necessary for Scripture to exempt the heirs;<span class="x" onmousemove="('comment',' That in such circumstances they are entirely exempt.');">²</span>

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