Related על פסחים 5:4

One who slaughters the Passover offering along with chametz on the fourteenth [of Nissan] transgresses a negative commandment, [but the] Passover offering itself is valid, and he fulfills his obligation through it with [respect to] the Passover offering. And whether he is the one who slaughters it, or the one who sprinkles its blood, or the one who offers it up [on the Altar, he is liable]. In what case does this apply? When one of the members of a collective [who will partake in the Paschal lamb] has chametz [in his possession]. If none of the members of the collective has chametz, he is exempt, but the one who pinches the neck of a bird inside [the Temple] with chametz on the fourteenth transgresses a negative commandment.

Rabbi Shimon says, [if] the Passover offering [is offered] on the fourteenth [along with chametz (see Minchat Yitzchak)] for its purpose, he is liable because [the offering] is valid [to be sacrificed on Passover], and [if] not for its purpose, he is exempt because it is disqualified. And [a Passover offering] on the intermediate days of the Festival -- for its purpose, he is exempt, because it is disqualified, but for a different purpose, he is liable, because it is valid. When does this apply? When they are fit to be brought as a Passover offering, but if they are not fit to be brought as a Passover offering, whether [it is sacrificed] for its purpose or not for its purpose, he is liable, because it is valid. Said Rabbi Shimon, a Passover offering on the fourteenth in its purpose is valid, and not for its purpose is disqualified. On the intermediate days of the Festival -- for its purpose, it is disqualified, and not for its purpose, it is valid. And when [else] does this apply? When it is fit to bring as a Passover offering, but if it is not fit to bring as a Passover offering, whether for its purpose or not for its purpose, it is valid.