The Bechor Korban (offering), the male firstborn of a cow, goat, or sheep that a person owns, has to be given over to the Kohen (priest), who then has to bring it as a Korban. The Ma'aser is every tenth animal of a person's newborn cows, goats, and sheep, which he has to offer as a Korban every single year. They would put all the newborn animals into a pen and have them leave one by one, counting them out. They would mark the tenth one with red paint, knowing that it was going to be designated for Ma'aser. It is brought to the Beit HaMikdash, where the animals are offered on the Mizbeach (altar), and the person eats the meat in Yerushalayim.
And the Pesach, the Korban Pesach (Passover offering): every single year, every person has to be registered as part of a group, or he can bring his own Korban Pesach on the day before the holiday of Pesach. These are considered to be Kodashim Kalim (offerings of lesser sanctity); they are in the category of Kodashim Kalim. They are slaughtered anywhere in the courtyard of the Beit HaMikdash. The blood is applied to one part of the Mizbeach, but the Kohen has to apply it to the part of the Mizbeach aligned with the base: the western and northern parts, the walls of the Mizbeach.
Shinui ba'achilatan, even though we group the Korbanot (offerings) over here together, when it comes to certain laws of eating them, there are differences. The Bechor is eaten only by the Kohanim (priests). The Ma'aser, every tenth animal, is eaten by anybody. The owner, his friends, and his guests eat it; none of it is given over to the Kohanim. Both of these Korbanot—the Bechor and the Ma'aser—are eaten anywhere in the city of Yerushalayim, and they are prepared in any way a person wants, for two days and a night. That means the day the Korban is offered, that night afterward, and then the following day.
But the Pesach is different: a Pesach, the Korban Pesach, is only eaten during the nighttime. It is sacrificed during the daytime and eaten the night afterward, and it is only allowed to be eaten until midnight. Once midnight hits, a person is not allowed to eat from the Korban Pesach. It can only be eaten by people who were counted for that Chaburah, who were counted as members of the group. They had to register beforehand, and they became part of that Korban Pesach, so it is only allowed to be eaten by those people. It is only allowed to be roasted; it cannot be cooked in any other way.