What does Exodus 2:14 mean?

Moses attempted to break up a fight between two of his fellow Hebrews. One of the Jewish fighters answers by calling out two points of hypocrisy. First, Moses was a Jew and yet lived among the Egyptians. Socially, at least, he was the last person with any authority to make judgments among the Hebrews. Moses was also a prince in one sense: Pharaoh's daughter had adopted him into the royal family (Exodus 2:10). He may have even been dressed in Egyptian clothing, further separating him from the culture of his own people. The question, then, can be re-phrased simply as "who are you to get involved in this?"

Second, the man implies that he knows about Moses' recent killing of an Egyptian who was beating a Hebrew (Exodus 2:11–12). This second point of hypocrisy questions how Moses can criticize violence when he himself has acted violently.

Learning that his crime was no longer a secret frightens Moses. He can be put to death himself (Exodus 2:15). Instead of worrying about the fight between the two Hebrews, Moses was now in fear for his own life. His courage turned to fear as he faced either the consequences of his actions, or escape.