Exodus 11:1-10; 12:29-36

"So the people of Israel did just as the LORD had commanded through Moses and Aaron. And that night at midnight, the LORD struck down all the firstborn sons in the land of Egypt, from the firstborn son of Pharaoh, who sat on his throne, to the firstborn son of the prisoner in the dungeon. Even the firstborn of their livestock were killed. Pharaoh and all his officials and all the people of Egypt woke up during the night, and loud wailing was heard throughout the land of Egypt. There was not a single house where someone had not died." 12:28-30
Every firstborn child of the Egyptians died, but the Israelite children were spared because the blood of the lamb had been smeared on their doorframes (passover). So begins the story of redemption, the central theme of the Bible.

Redemption means - "to buy back" of "to save from captivity by paying a ransom." One way to buy back a slave was to offer an equivalent or superior slave in exchange. That is the way God choose to buy us back - he offered his Son in exchange for us.

In the Old Testament times, God accepted symbolic offerings. Jesus had not yet been sacrificed, so God accepted the life of an animal in place of the life of the sinner. When Jesus came, he substituted his perfect life for our sinful lives, taking the penalty for sin that we deserve. Thus he redeemed us from the power of sin and restored us to God. Jesus' sacrifice made animal sacrifice no longer necessary.

We must recognize that if we want to be freed from the deadly consequences of our sin, a tremendous price must be paid. But we don't have to pay it. Jesus Christ, our substitute, has already redeemed us by his death on the cross. Our part is to trust him and accept his gift of eternal life. Our sins have been paid for, and the way has been cleared for us to begin a relationship with God.

Taken from the NLT Life Application Study Bible