Reference for Pesachim 157:23
איכא דאמרי אמר רב כהנא מחצה על מחצה אינו כרוב טהורין עושין את הראשון
And as for the flesh, every one that is clean may eat thereof.<span class="x" onmousemove="('comment',' Lev. VII, 19.');"><sup>25</sup></span> Wherever we read 'and the flesh that toucheth any unclean thing shall not be eaten,' we [also] read, 'and as for the flesh, every one that is clean may eat thereof;' and wherever we do not read, 'and the flesh that toucheth any unclean thing shall not be eaten' we [also] do not read, 'and as for the flesh, every one that is clean may eat thereof.'<span class="x" onmousemove="('comment',' I.e., the two are interdependent. Since the flesh is now eaten unclean, unclean persons too may eat it.');"><sup>26</sup></span> It was stated: Behold, if the Israelites were half [of them] clean and half unclean, Rab said: Half against is as a majority; while R'Kahana said: Half against half is not as a majority. Rab said, Half against half is a majority'; [hence] these sacrifice<span class="x" onmousemove="('comment',' Lit., 'do'.');"><sup>27</sup></span> by themselves, while those sacrifice by themselves.<span class="x" onmousemove="('comment',' They must all observe the first Passover. The clean must not show themselves to be defiled, for');"><sup>28</sup></span> 'While R'Kahana said: Half against half is not as a majority'; [hence] the clean observe the first [Passover], while the unclean observe the second. Others say, R'Kahana said: Half against half is not as a majority: the clean observe the first [Passover],