Moses continues to drag his feet and doesn't want to participate in what God is asking him to do and God seeks to put him to death. It's only when Moses' wife Tziporah steps in and acts as the family patriarch and priest by circumcising their son Gershon, does God allow Moses to continue. Despite this provision, God ends up splitting up the duties of Leader and Priest between Moses and Aaron as a concession to Moses' continued resistance to his new position.