Reference for Bava Batra 88:9

הכא במאי עסקינן במכיר בה שהיא בת חמורו

or draft form')? — We assume here that the seller sold [the cow or the garment] immediately after himself acquiring it.<span class="x" onmousemove="('comment',' And therefore we are quite certain that he did not mortgage it for a debt of his own. Hence he may testify to the purchaser's title, as he has no personal interest in the matter. ');">⁹</span>

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