The Feast of Unleavened Bread or Festival is one of the seven feasts of God. It takes place the day immediately following Passover and for seven days the people of Israel were to eat unleavened bread (bread without yeast). Often the feast is overlapped with the immediately proceeding Passover, but are actually two separate events (that are meant to be in conjunction with each other).
For seven days bread with yeast could not be eaten, hence unleavened bread would have to be eaten. Anyone who consumed anything with yeast during this time would have to be isolated from the rest of the community of Israel (whether they were Hebrew or not). On the first day of the feast a sacred priestly assembly was to be held and again on the seventh day; during these times no regular work was to be done except for preparing unleavened bread.
Also during the Feast special food offerings was required to be given along with the regular offerings. The food offering would have to consist of two young bulls, a ram, and seven year-old male lambs- all these without defect or blemish. Alongside every bull three-tenths of an ephah of the best flour-oil mixture was to be sacrificed. For the ram two-tenths of an ephah of the best flour-oil mixture was to be given and for each lamb one-tenth. Further a male goat sin offering had to be sacrificed as an atonement sin offering.
Main article: Passover#Celebrations