Moses' action of killing an Egyptian who was beating a Hebrew is a key event that portrays Moses as a leader. This act marked a decisive moment in his life, where he took action to defend his people (the Israelites). Although this act was impulsive and resulted in Moses fleeing to Midian, it is an important indication of his growing awareness of his role in delivering the Israelites.

Exodus 2:11-12 (RSV):

“One day, when Moses had grown up, he went out to his people and looked on their burdens; and he saw an Egyptian beating a Hebrew, one of his own people. He looked this way and that, and seeing no one, he slew the Egyptian and hid him in the sand.”

This act of defending his people set the stage for Moses' eventual leadership role in delivering the Israelites from slavery in Egypt.