Pesakh rishon and Pesakh sheni and the rule of three TB Pesakhim 95

 Today’s daf TB Pesakhim 95 delineates the difference between Pesakh rishon and Pesakh sheni. To facilitate memorization, the Gemara likes to organize ideas in groups of three. 1, Pesakh rishon and Pesakh sheni share all the laws that relate directly to the korban Pesakh (מִצְוָה שֶׁבְּגוּפוֹ), for example, the lamb or the goat must be roasted. 2, They also share all the laws that are accessory to the korban Pesakh (מִצְוָה שֶׁעַל גּוּפוֹ,), for example, the Passover sacrifice must be eaten with matza and marror, bitter herbs. 3, Any other aspect of Passover is only observed on Pesakh rishon and not on Pesakh sheni (מִצְוֹת שֶׁלֹּא עַל גּוּפוֹ), for example, the removal of all hmatez. 

In a baraita the rabbis classify the laws into three categories.

The first category are positive commitments (מִצְוַת עֲשֵׂה). “The Sages taught in a different baraita: The verse states: ‘According to the entire statute of the Paschal lamb they shall offer it’ (Numbers 9:12). One might have thought that just as at the time of the sacrifice of the Paschal lamb on the first Pesakh it is prohibited to own leaven due to the prohibitions of: It shall not be seen, and: It shall not be found, so too, at the time of the sacrifice of the Paschal lamb on the second Pesakh it is prohibited to own leaven due to the prohibitions of: It shall not be seen, and: It shall not be found. Therefore, the Torah states: 'They shall eat it with matzot and bitter herbs’ (Numbers 9:11), which indicates that the other mitzvot pertaining to the first Pesakh do not apply on the second.” (Sefaria.org translation)

The second category are negative commitments that can be rectified (מִצְוַת לֹא תַעֲשֶׂה שֶׁנִּיתָּק לַעֲשֵׂה). “The baraita continues: And from here I have derived only that positive mitzvot related to the first Pesakh apply on the second Pesakh; from where do I derive that the same is true of negative mitzvot? The verse states: ‘They shall leave none of it to the morning, nor break a bone in it’ (Numbers 9:12). The baraita continues: And from this verse I have derived only that a negative mitzva whose violation can be rectified by the fulfillment of a positive mitzva applies on the second Pesakh, e.g., the prohibition of leaving over meat from the Paschal lamb until morning, which can be rectified by the positive mitzva of burning the leftovers;” (Sefaria.org translation)

The third category is negative commandments (מִצְוַת לֹא תַעֲשֶׂה) “from where is it derived that the same is true of a full-fledged negative mitzva? The verse states: 'They shall not break a bone in it.' It may be concluded from these examples that just as the detail, i.e., the specific mitzvot mentioned in these verses, is explicit and includes a positive mitzva, a prohibition whose violation can be rectified by the fulfillment of a positive mitzva, and a full-fledged negative mitzva; so too, every positive mitzva, every prohibition whose violation can be rectified by the fulfillment of a positive mitzva, and every full-fledged negative mitzva is included.” (Sefaria.org translation)