Halakhah for Numbers 9:13

That is that He commanded us to slaughter the Pesach-offering on the fourteenth of Nissan in the afternoon. And one who transgresses this command and does not sacrifice it in its time is liable for excision - whether it is a man or a woman. And it has already been explained in the Gemara (Pesachim 91b) that the first Pesach is a commandment [also] for women and that it pushes off the Shabbat. That means to say, its sacrifice must be on the fourteenth [even when it] comes out on a Shabbat, [for women] - just like for every Jewish man. And the Torah's language about the liability for excision is His saying, "and refrains from offering the Pesach-offering, that person shall be cut off" (Numbers 9:13). And at the beginning of Keritot (Keritot 2a) when it lists the commandments for which one who transgresses them becomes liable for excision - and they are all negative commandments - it says, "And the Pesach-offering and circumcision, among the positive commandments." And we already mentioned this in the introduction (Sefer HaMitzvot, Shorashim 14). And this commandment has already been explained in Pesachim. (See Parashat Bo; Mishneh Torah, Paschal Offering 1.)