Reference for Zevachim 57:1

לא יערב בו מחשבות אחרות

other intentions must not be mingled therein.<span class="x" onmousemove="('comment',' The animal is piggul only if this, sc. to eat it after time, was his only intention. But if he also expressed another which would disqualify the sacrifice without rendering it piggul, this intention negatives the other; cf. Mishnah on ');">¹</span> 'An abhorred thing [piggul]': this refers to [the intention of eating it] without bounds.<span class="x" onmousemove="('comment',' Since the intention of eating it after time has already been dealt with.');">²</span>

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