Reference for Menachot 111:15
אלא לעולם כדקאמרינן מעיקרא אותו בצפון ואין השוחט בצפון ודקא קשיא לך מדר' אחייה נפקא דר' אחייה לאו למעוטי שוחט בצפון הוא דאתא אלא הכי קאמר אין השוחט בצפון אבל מקבל בצפון
But surely this is so with the guilt-offering because it is a Most Holy offering.<span class="x" onmousemove="('comment',' Whereas the Passover-offering is of the Less Holy offerings.');"><sup>16</sup></span> And if one were to argue the case from all these offerings, [one could retort that] this is so with these mentioned because they are all Most Holy offerings! - Rather [we must say that the interpretation] is indeed as stated previously: 'It' must be on the north side but the slaughterer need not be on the north side; and as for your objection 'Is not this to be derived from R'Ahiyah's teaching? ' [I say that] R'Ahiyah comes [not to teach] that the slaughterer need not be on the north side; he teaches rather that, in contradistinction from the slaughterer who need not be on the north side,<span class="x" onmousemove="('comment',' This is derived from the term 'it' (Lev. IV, 24) stated in connection with the sin-offering of a ruler.');"><sup>17</sup></span>