"The Substitute" (Exodus 11:1-12:30). The last of the ten plagues is unique in two ways. First, it is the one plague that clearly could have affected the Israelites as well as the Egyptians. It's also the plague that provides the basis for an important image associated with Jesus in the New Testament. As we commemorate Christ's death as our "Passover lamb," we'll consider why that image is so powerful.