Zevachim 57 - First-born, Tithe, and Passover Sacrifices
The first-born, tithe, and Passover sacrifices are the remaining holy offerings. The first-born offering is a male offspring of a cow, sheep or goat; it is given to a Kohen, who offers it as a sacrifice. The animal tithe is taken each year from the newborns of the herds and flocks. Each tenth animal is designated as the tithe one, and then the owner takes it to Jerusalem, brings it as a sacrifice, and eats it there, together with his family and friends.
These offerings are slaughtered anywhere in the Courtyard, and their blood requires only one application on the Altar, provided that it is done against the foundation. The foundation is the one-cubit step at the bottom of the Altar; it ran along the western and northern sides, plus another cubit to the east and to the south sides.
The Passover offering is special in that it is eaten only at night until midnight, only by those who have registered beforehand, and only roasted.
One who desires to reach God is called "the firstborn", and one deep feeling of this is sufficient, provided that it is sincere - that is, done against the foundation (the very depth) of the heart.
Art: Julien Dupre - A Shepherd And His Flock