Passover is the celebration of the time God and Moses led the Israelites out of Egypt and freed them from slavery under the Pharaoh. Tradition instructs that Jews read during the Passover celebration: “And you shall tell your son in that day, saying, 'This is done because of what the Lord did for me when I came up from Egypt.'"
The Jewish holiday gets its name from the 10 plagues God unleashed against the Egyptians when Pharaoh would not let the Israelites leave. For the tenth plague, God told the Jews to mark their doors with lamb’s blood so that he wouldn't kill their first-born sons. The Egyptians weren't so lucky. Read the full story from the book of Exodus below:
Moses then summoned all the elders of Israel and said to them, "Go, pick out lambs for your families, and slaughter the passover offering. Take a bunch of hyssop, dip it in the blood that is in the basin, and apply some of the blood that is in the basin to the lintel and to the two doorposts. None of you shall go outside the door of his house until morning. For when the Lord goes through to smite the Egyptians, He will see the blood on the lintel and the two doorposts, and the Lord will pass over the door and not let the Destroyer enter and smite your home.
"You shall observe this as an institution for all time, for you and for your descendants. And when you enter the land that the Lord will give you, as He has promised, you shall observe this rite. And when your children ask you, 'What do you mean by this rite?' you shall say, 'It is the passover sacrifice to the Lord, because He passed over the houses of the Israelites in Egypt when He smote the Egyptians, but saved our houses.'" The people then bowed low in homage. And the Israelites went and did so; just as the Lord had commanded Moses and Aaron, so they did.
In the middle of the night the Lord struck down all the first-born in the land of Egypt, from the first-born of Pharaoh who sat on the throne to the first-born of the captive who was in the dungeon, and all the first-born of the cattle. And Pharaoh arose in the night, with all his courtiers and all the Egyptians -- because there was a loud cry in Egypt; for there was no house where there was not someone dead. He summoned Moses and Aaron in the night and said, "Up, depart from among my people, you and the Israelites with you! Go, worship the Lord as you said! Take also your flocks and your herds, as you said, and begone! And may you bring a blessing upon me also!"
The Egyptians urged the people on, impatient to have them leave the country, for they said, "We shall all be dead." So the people took their dough before it was leavened, their kneading bowls wrapped in their cloaks upon their shoulders. The Israelites had done Moses' bidding and borrowed from the Egyptians objects of silver and gold, and clothing. And the Lord had disposed the Egyptians favorably toward the people, and they let them have their request; thus they stripped the Egyptians.
The Israelites journeyed from Raamses to Succoth, about 600,000 men on foot, aside from children. Moreover, a mixed multitude went up with them, and very much livestock, both flocks and herds. And they baked unleavened cakes of the dough that they had taken out of Egypt, for it was not leavened, since they had been driven out of Egypt and could not delay; nor had they prepared any provisions for themselves.
The length of time that the Israelites lived in Egypt was 430 years; at the end of the 430th year, to the very day, all the ranks of the Lord departed from the land of Egypt. That was for the Lord a night of vigil to bring them out of the land of Egypt; that same night is the Lord's, one of vigil for all the children of Israel throughout the ages.
The Lord said to Moses and Aaron: This is the law of the passover offering: No foreigner shall eat of it. But any slave a man has bought may eat of it once he has been circumcised. No bound or hired laborer shall eat of it. It shall be eaten in one house: You shall not take any of the flesh outside the house; nor shall you break a bone of it. The whole community of Israel shall offer it. If a stranger who dwells with you would offer the passover to the Lord, all his males must be circumcised; then he shall be admitted to offer it; he shall then be as a citizen of the country. But no uncircumcised person may eat of it. There shall be one law for the citizen and for the stranger who dwells among you.
And all the Israelites did so; as the Lord had commanded Moses and Aaron, so they did.
That very day the Lord freed the Israelites from the land of Egypt, troop by troop.