Mishnayos Pesachim Perek 6 Mishnah 6

The mishna continues with another halakha with regard to the Paschal lamb: If one slaughtered a Paschal lamb on Shabbat and mistakenly intended it for those who cannot eat it, such as sick or elderly people who are unable to eat the meat, or for those who did not register for it, or for the sake of the uncircumcised or for those ritually impure, the offering is disqualified and he is liable to bring a sin-offering for his unnecessary act of slaughter. If, however, he slaughtered it for those who can eat it and for those who cannot eat it, or for those who registered for it and for those who did not register for it, or for the circumcised and for those who are uncircumcised, or for those who are ritually impure and those who are ritually pure, he is exempt. Since a Paschal lamb slaughtered with dual intentions of these types is valid, the act of slaughter was justified. If he slaughtered it and it was found to have a blemish, the offering is disqualified, and he is liable to bring a sin-offering for having unwittingly performed a prohibited labor on Shabbat, as he should have examined the animal before it was slaughtered. If he slaughtered it and it was found to have a hidden condition that would cause it to die within twelve months [tereifa] and that could not have been discovered before the slaughter even if it were examined properly, the offering is disqualified, but he is exempt from bringing a sin-offering. This is not a case of shogeg, unwitting violation of Shabbat, but rather of ones, an unavoidable accident. If he slaughtered it and afterward it became known that the owners had withdrawn from it and registered for a different Paschal lamb, in which case this one was slaughtered unnecessarily, as no one was registered for it, or it became known that they had died or became ritually impure, in all these cases he is exempt from bringing a sin-offering, because he slaughtered with permission. At the time of the slaughter, he did not know and had no reason to suspect that the offering would be disqualified.

שְׁחָטוֹ שֶׁלֹּא לְאוֹכְלָיו וְשֶׁלֹּא לִמְנוּיָיו, לַעֲרֵלִין וְלִטְמֵאִין, חַיָּב. לְאוֹכְלָיו וְשֶׁלֹּא לְאוֹכְלָיו, לִמְנוּיָיו וְשֶׁלֹּא לִמְנוּיָיו, לְמוּלִין וְלַעֲרֵלִין, לִטְהוֹרִים וְלִטְמֵאִים, פָּטוּר. שְׁחָטוֹ וְנִמְצָא בַעַל מוּם, חַיָּב. שְׁחָטוֹ וְנִמְצָא טְרֵפָה בַסֵּתֶר, פָּטוּר. שְׁחָטוֹ וְנוֹדַע שֶׁמָּשְׁכוּ הַבְּעָלִים אֶת יָדָם, אוֹ שֶׁמֵּתוּ אוֹ שֶׁנִּטְמְאוּ, פָּטוּר, מִפְּנֵי שֶׁשָּׁחַט בִּרְשׁוּת: