Reference for Pesachim 120:1
אלא לאו בעבודה אחת ומדסיפא בעבודה אחת רישא נמי בעבודה אחת
Hence it surely refers [also] to one service,<span class="x" onmousemove="('comment',' I.e., also to one service.');"><sup>1</sup></span> and since the second clause refers [also] to one service, the firs clause too refers [also] to one service! - What argument is this: the one is according to its nature, while the other is according to its nature: the second clause refers [also] to one service,<span class="x" onmousemove="('comment',' This will not have quite the same meaning as the same phrase used before. There it obviously meant that it treats of one service only. Here however the meaning is this: even in the case of one service the sacrifice is fit, this law holding good in the case of both one service or two services. Thus, if this intention, viz., that he was killing it for eaters and non-eaters, was expressed at the slaughtering, the sacrifice is fit, because eaters were included. While it may also refer to two services, as explained on p. 301, n. 7.');"><sup>2</sup></span>