Zevachim 57 - First-born, Tithe, and Passover Sacrifices
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
