Reference for Zevachim 98:3
אמר ליה מר זוטרא בריה דרב מרי לרבינא אימא כי אהדריה קרא לגבי מתן דמים ואימורין דבעי כהונה אבל שחיטה דלא בעיא כהונה לא מיבעי צפון
Mar Zutra son of R'Mari said to Rabina: Yet say, When Scripture restored it [to the general proposition] [it was only] in respect of the presentation of the blood and emmurim, since this requires priesthood;<span class="x" onmousemove="('comment',' It must be done by a priest. Hence the restoration to the general proposition shews that its emurim and some of the blood must be presented at the altar, in addition to its being applied to the right thumb etc.');"><sup>5</sup></span> but slaughtering, which does not require priesthood, does not require the north [either]?<span class="x" onmousemove="('comment',' But for 'and he shall kill' etc. In that case it is not a repetition, and does not teach that it is indispensable.');"><sup>6</sup></span>