Halakhah do Wyjścia 34:25

To not leave the entrails of the Pesach sacrifice to stay overnight: Not to leave the entrails of the Pesach sacrifice until the morning, [such] that they not be sacrificed, and [so] become disqualified with this leaving over and become called notar (what is left over); as it is stated (Exodus 23:18), "and the fat of My festival offering shall not be left lying until morning." And the same is true of other portions to be burned in other sacrifices. And the language of Mekhilta d'Rabbi Yishmael 23:18 is "'The fat shall not be left lying' - the verse comes to teach that the fats are disqualified by lying over." And this preventing was already repeated in another place, as it is stated (Exodus 34:25), "and the sacrifice of the festival of Pesach shall not be left lying until morning."

He prohibited us from slaughtering the Pesach-offering over chametz (leavened grain products). And that is His, may He be exalted, saying, "You shall not sacrifice the blood of My sacrifice over chametz" (Exodus 23:18). And the prohibition about this was already repeated with this exact language, "do not slaughter, [etc.]" (Exodus 34:25). And its content is that at the time of the slaughtering of the Pesach-offering - and that is in the afternoon (of the 14th of Nissan) - one should not have chametz in his possession, nor in the possession of the one who sprinkles [the blood], the one who slaughters [the sacrifice], the one who burns [it] or any of the members of the [eating] group. And anyone of them who has chametz with them at that time is lashed. And in the Mekhilta (Mekhilta d'Rabbi Yishmael 23:18:1): "'You shall not slaughter over chametz' - you shall not slaughter the Pesach-offering and still have chametz in existence." And the laws of this commandment have already been explained in the fifth [chapter] of Pesachim. (See Parashat Mishpatim; Mishneh Torah, Paschal Offering 1.)

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.)