Re'eh - Sh'vi'i
No Doggie Bags on Passover
Every first-born male from the sheep and cattle is consecrated to God, so don't work that ox or shear that sheep. They must be eaten by the kohanim in Jerusalem. But if the animal has a disqualifying blemish, it may not be sacrificed to God. It may then be eaten at home, even by ritually unclean people, like any other non-sacrificial meat.
At this point, Moshe recaps the three Festivals: Pesach, Shavuos and Succos.
Pesach (Passover) falls in the spring and commemorates the exodus from Egypt. The Passover sacrifice must be eaten in Jerusalem and all leaven must be cleared away. Matzah - unleavened bread - is eaten that entire week because of the way the Jews left Egypt in haste. The sacrifice must be eaten that night - no leftovers allowed! The first and last days of the holiday are Yom Tov and have Sabbath-like limitations on labor.
Shavuos is seven weeks later. (The Torah doesn't say as much, but Shavuos commemorates the giving of the Torah at Sinai, which occurred seven weeks after the exodus.) Everyone is to rejoice in Jerusalem.
Succos is in the fall, celebrated for a week in Jerusalem. God will bless the Jews' produce and their other labors.
All males shall appear at the designated place (the Temple in Jerusalem) on these three occasions. They are not to come empty-handed. Rather, they are to bring an offering commensurate with the blessings that God has granted them.