Abraham's grandson Jacob, also called Israel, had twelve sons. Out of jealousy, the brothers sold young Joseph into slavery in Egypt. God was with Joseph, and he rose to govern Egypt for Pharaoh. When famine came, he forgave his brothers and saved his whole family.
Centuries later, a new Pharaoh feared the growing Israelites and made them slaves. Baby Moses was saved from Pharaoh's cruel order and raised in the palace, but later he fled to the desert. There God spoke to him from a bush that burned but was not burned up.
God revealed His name: “I AM WHO I AM” (in Hebrew, YHWH). God simply is. He has no beginning and no end, and He is faithful forever. Out of reverence, Jewish people do not say this name aloud; they say “the Lord” instead, and so do our Bibles.
Moses and his brother Aaron told Pharaoh, “Let my people go.” Pharaoh refused, and God sent ten plagues. Before the last plague, each Israelite family sacrificed a spotless lamb, marked their doorposts with its blood and ate a meal ready to travel. Death passed over their homes. This was the first Passover.
Pharaoh let them go, then chased them with his army. God parted the Red Sea, and Israel walked through on dry ground to freedom. The Exodus became the great sign of God's saving power, and Jewish families still remember it every year at Passover.
The Exodus points to Jesus. He is the true Lamb of God, whose blood saves us. He celebrated the Last Supper at Passover time. And in Baptism we pass through the water from slavery to sin into the freedom of God's children.