The death of the firstborn was the tenth and final plague God sent upon Egypt, described in the Book of Exodus, where every firstborn Egyptian male and livestock died, sparing only the Israelites who marked their doorposts with lamb’s blood, leading Pharaoh to finally release the enslaved Hebrews, an event commemorated as Passover. This devastating plague struck all social classes and challenged Egyptian beliefs in their gods and Pharaoh’s divinity, culminating in mass mourning and compelling Egypt’s release of the Israelites after centuries of bondage.