As Moses prepares to return to Egypt, God reiterates His message to Pharaoh, this time with the promise that if Pharaoh disobeys, that God will punish him by taking his firstborn son. Later God approaches to execute Moses for his sin but is appeased when Moses’ firstborn son is circumcised. Both situations illustrate God’s wrath towards sin and foreshadow His provision of a substitute through the “Firstborn.”