This is a true story. It comes from Exodus Chapter 12 in your Bible.
In the Old Testament, we are reminded again and again through the stories that when God made a promise, He kept it. Even when the perfect Creation was ruined, God made a plan to save us from sin. He loved us enough to sacrifice something very special to Him.
In Exodus chapter 12 of the Bible, the story of the Passover takes place during the time when the Israelites were enslaved in Egypt. God sends a series of plagues to persuade Pharaoh to release the Israelites, but Pharaoh remains stubborn.
As the final plague, God declares that the firstborn of every household in Egypt will die, both humans and animals. However, God provides a way for the Israelites to be spared from this plague. He instructs them to select a male lamb or goat without blemish on the 10th day of the month and keep it until the 14th day. Then, at twilight, they are to slaughter the lamb and apply its blood on the doorposts and lintel of their houses. They are to roast and eat the lamb along with unleavened bread and bitter herbs.
That night, God passes through the land of Egypt, and when He sees the blood on the doorposts, He "passes over" those houses, sparing the firstborns inside. However, in Egypt, there is great mourning as the firstborn of both humans and animals are struck down.
Pharaoh finally relents and allows the Israelites to leave. They quickly gather their belongings and, under Moses' leadership, they depart from Egypt, beginning their journey towards the Promised Land.
The Passover event is significant for the Israelites as it marks their liberation from slavery and the beginning of their journey towards freedom. It also establishes the institution of the Passover feast as a lasting memorial for the Israelites to remember God's deliverance. Later in the Bible, the Passover becomes a significant symbol pointing to Jesus Christ as the ultimate Passover Lamb, whose blood saves believers from the consequences of sin and offers eternal life.