The Passover is the feast that celebrates and remembers God’s liberation of Israel from Egypt.
After Joseph saved Egypt from starvation in Genesis 41, the Israelites lived in Egypt as guests. The pharaoh at the time was very good to Joseph and the Israelites were treated well under his kingship. When that pharaoh died and a new one came in, he didn’t treat the Israelites well. Eventually the Egyptians forget about Joseph and enslaved the Israelites for hundreds of years (Exodus 1:6 – 14). Overburdened with work and mistreatment, the Israelites suffered a great deal and called out to God. God responded to their cry and raised a great leader, Moses who challenged the Pharaoh and Egypt’s power.
The book of Exodus explains how God freed his people from Pharaoh’s oppression and how Egypt suffered under the 10 plagues that God sent. During the last plague God killed all the first borns – both human and animal first borns. God however gave his people a way to escape the destruction – through the blood of a perfect lamb. When its blood was smeared on the lintels of the door, the angel of the Lord would pass over that home and accept the blood of the sacrificed lamb in place of the first born of the family. God gave specific instructions to the Israelites on how to eat this lamb – they were to eat it roasted by fire, with bitter herbs and unleavened bread. They were to eat it standing with their staff in hand and ready to depart Egypt at any moment.
The Passover feast was to be repeated by Israel throughout the generations as a monument forever. God gave specific instructions on how this Passover event was to be commemorated in Exodus 12.Each Israelite family was to kill an unblemished lamb, collect its blood in a basin, and then apply the blood to the lintel and doorposts of their houses. It is probable that, in many houses, the basins were first set down on the floor before the hyssop was dipped in to apply the blood; so after the blood was applied, we have blood at the feet, blood above the head, blood on the left at arm level and blood on the right, possibly in prefigurement of the cross that our Lord died on.