Reference for Zevachim 31:11

מה ליושב שכן פסול לעדות מיושב ת"ח

If one who is sitting profanes [the sacrifice] if he officiates, though he may eat [thereof when sitting]; is it not logical that a zar, who may not eat, profanes [it] if he officiates? As for one who is sitting, the reason may be because he is unfit to testify!<span class="x" onmousemove="('comment',' A witness may not sit when giving his testimony. Of course, this has nothing to do with sacrifices, but in order to refute an argument based on an inference a minori it is sufficient to shew that the premise is subject to a particular restriction from which the other is free.');">¹²</span>

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