The story of Passover can be traced all the way back to the book of Exodus!
On the night of the 15th of Nissan, the tenth and final plague, the killing of the firstborn Egyptians takes hold. God instructs the Jewish people to slaughter a ram and use its blood to mark their doorposts. And then, during the night, the angel of death passes over all the Jewish households. With so much devastation, Paroah's resolve is broken, and he hurries the Jewish people out of Egypt. With barely hours until they depart, the people bake bread, but because of the rush, there is no time for the bread to rise or leaven, leaving them with flat Matzo crackerbread. On that day, 600,000 Jewish souls left Egyptian bondage on the way to becoming God's people, receiving the Torah at Mount Sinai, and eventually arriving at the borders of Israel!