He prohibited us from leaving over the innards of the Pesach-sacrifice that were not sacrificed, until they became disqualified by laying overnight. And that is His saying, "you shall not leave the fat of My festival offering until morning" (Exodus 23:18). And the law is the same for the innards of other sacrifices. And the language of the Mekhilta (Mekhilta d'Rabbi Yishmael 23:18:2) is, "'You shall not leave the fat of My festival offering' - Scripture comes to teach about the fats, that they are disqualified by remaining on the floor overnight." And the prohibition about this content was already repeated with different language - His saying, "and the sacrifice of the holiday of Pesach shall not be left lying until morning" (Exodus 34:25). (See Parashat Ki Tissa, Mishpatim; Mishneh Torah, Paschal Offering 1.)