What guidelines were the people of Israel given regarding Passover sacrifice?

The Passover or "Festival of Unleavened Bread" is one of the most important feasts of the Israelite people's calendar.

The account in the book of Exodus (chapters 12-14) tells how God "passed over" the homes of the Israelites and killed all the firstborn children of the Egyptians, after they had refused for a long time to free the Israelite slaves. According to the biblical narrative, the last of ten plagues caused the death of the Egyptian firstborn, including the Pharaoh's son. When the Pharaoh and his officials finally yielded and let the Israelites go, the latter left the land of Egypt so suddenly that they were not able to let their bread dough rise before baking it, and they thus ate unleavened bread on their journey.

The regulations concerning the Passover sacrifice are given in Exodus 12:1–28.

Here is a summary of these guidelines:

- The sacrifice was to be a male lamb or goat, one year old and without blemish.

- The animal was to be selected on the tenth day of the first month (Nisan) and kept until the fourteenth day of the month.

- On the evening of the fourteenth day, the animal was to be slaughtered at twilight.

- The blood of the animal was to be sprinkled on the doorposts and lintel of the house where the Israelites were staying.

- The meat of the animal was to be roasted whole and eaten with unleavened bread and bitter herbs.

- No one was to be allowed to leave the house during the night of Passover.

- Anyone who was not a member of the household had to leave or could eat of the sacrificial meal on the condition of conforming to the law that only circumcised males may partake of the sacred food.

- Any remaining meat was to be burned before sunrise.

- The Passover sacrifice was to be celebrated annually in remembrance of the Israelites' liberation from slavery in Egypt.