When a group of men are unable, due to their impurity, to offer the Pesach sacrifice one year after the Exodus, the laws of Pesach Sheni are taught: And Hashem spoke to Moshe, saying, “Speak to the Children of Israel, saying: If any man, of you or of your generations, shall become impure by a dead body, or on a distant journey, he shall offer the PESACH to Hashem, in the second month, on the fourteenth day, in the afternoon, shall they offer it; with matzot and bitter herbs shall they eat it. They shall not leave over anything of it until morning, nor shall they break a bone of it: according to all the ordinances of the PESACH shall they offer it. But a man who was pure, and was not on a journey, yet refrained from offering the PESACH, then that soul shall be cut off from its people, because he did not sacrifice the sacrifice of Hashem in its appointed time; that man shall bear his sin. And if a convert dwell among you, and will offer a PESACH to Hashem, according to the ordinance of PESACH and according to its law, so shall he do. One ordinance shall there be for you, for the convert and for the native of the land” (Bamidbar 9:9-14).
All laws that apply to the actual sacrifice itself – for example, to eat it roasted with matzot and bitter herbs, not to leave any over, and not to break any of its bones – apply to Pesach Sheni as they did to the first Pesach. On the other hand, during Pesach Sheni one may own chametz, and Hallel is not recited when it is eaten (see Rambam, “Laws of the Pesach Sacrifice”, Chapters 5- ).
Let us take this opportunity to reexamine our most basic assumptions about our terminology for Passover. In our usage, the terms “Pesach” and “Chag HaMatzot” are synonyms. However, the Tanach does not use them interchangeably: In the first month, on the fourteenth of the month during the afternoon, is Pesach to Hashem. And on the fifteenth day of this month is the Festival of Matzot to Hashem: for seven days shall you eat matzot (Vayikra 23:5-6).
Ibn Ezra and Chizkuni (R. Chizkiya ben Manoach, mid-13th Century) point out that the “day of Pesach” begins on the day of the 14th of Nissan (when the Paschal sacrifice is offered) and continues through the following night (when the sacrifice is eaten); this is so because, when it comes to sacrifices, the night always follows the day (Chullin 83a; Temurah 14a). Chag HaMatzot is the seven-day period starting on the night of the 15th until the 21st. Thus, Seder night is an overlapping of the end of PESACH and the beginning of Chag HaMatzot.
Now we can understand such verses as: And they traveled from Raameses in the first month, on the fifteenth day of the first month, on the day after the Pesach (Bamidbar 33:3). And the Children of Israel that were present kept the Pesach at that time, and the festival of matzot for seven days (Divrei HaYamim II 35:17).
It is in this light that we should understand the following: And they ate of the produce of the land on the day after the Pesach [i.e., the 15th] matzot and roasted ears on that very day (Yehoshua 5:11). In the first month on the fourteenth day shall the Pesach be for you; a festival of a week of days shall matzot be eaten (Yechezkel 45:21). Sefer HaChinuch (ascribed to either R. Aharon HaLevi or R. Pinchas HaLevi of Barcelona, mid-13th Century) says that we are given a second opportunity for the Pesach sacrifice because the miracles of Pesach demonstrate “a great fundamental in the religion,” namely that Hashem is the Creator. But, then why is there no “Chag HaMatzot Hasheni”? Can it be only because Chag HaMatzot does not have the requirements of purity and presence in Jerusalem? Or might there be some more fundamental reason? Also, when teaching about Pesach Sheni, why does the Torah restate the obligation of a convert? After all, it was mentioned before in Shemot (12:48). Ramban answers that that verse might have referred only to Pesach in Egypt on the eve of the Exodus; now we learn that, for all time, a convert must offer the Pesach sacrifice.
Rashi, quoting Mechilta and Sifri, answers differently: “One might think that anyone who converts must offer the Pesach sacrifice immediately. Therefore the text states, One ordinance, etc. Rather, this is its meaning: And if a convert dwell among you, and he comes to offer the Pesach offering with his fellows, according to the ordinance of PESACH and according to its law, … shall he do.” But, why would it have occurred to us to require a new convert to bring the Pesach sacrifice, no matter when he converts? Even though it is possible to read the verse this way, is it a reasonable reading? Baer Hetev (R. Moshe Mat, c. 1551-c. 1606) answers that a Jew offers the Pesach sacrifice because he makes the transition from slavery to freedom. A convert undergoes a similar transformational experience. This might have led us to conclude that he should bring the sacrifice as part of his conversion process, had it not been for the verse that equates him to every other “citizen” of the Jewish people.
Ohr HaChayim (R. Chayim ben Moshe ibn-Attar, 1696-1743) goes further. Even though the convert’s forebears were not liberated in Egypt, the “root of his soul” was there, and was freed, along with all the Children of Israel.
We see therefore that, separate from the seven-day Chag HaMatzot, Pesach, the 14th of Nissan and the following night, is a reenactment of the moment before the Exodus. No Jew should be deprived of the opportunity to experience that moment.