Typology is a repetition of patterns that represent the type of things God does by using the events of the past to show what God will do in the future. One specific example of this is the Passover lamb. During the days of Moses, the Israelites were enslaved by the Egyptians and God was planning to rescue them and set them free. He was bringing judgment upon the Egyptians but promised to pass over the Israelites if they slaughtered an unblemished lamb and used its blood to cover both sides of their doorframes. While there is no known theological reason for using the blood of a lamb, this event demonstrates the principle of how obedience and faith bring forth mercy and salvation. The Israelites were saved and commanded to celebrate that day every year as a reminder of God’s goodness.
Jesus’ death on the cross took that demonstration even further. He lived a sinless life and was called a “lamb without blemish or defect”. He shed His precious blood on the cross, taking the judgment meant for us in order to bring forth mercy and salvation. According to 1 Corinthians 5:7, He became for us the Passover lamb. Jesus typologically fulfilled the substitutionary death of the Passover lamb. To illustrate this point even further, Jesus was crucified during the Jewish Passover celebration.
Just like the Israelites, we are all sinners who fall short of the glory of God. Because God is just, the wages of sin are death. The shedding of pure and perfect blood is a means of escape from judgment. An unblemished lamb was sacrificed in the Old Testament as a typology for the unblemished Savior who was sacrificed in the New Testament.