(13) When he went out the next day, he found two Hebrews fighting; so he said to the offender, “Why do you strike your fellow?”
(14) He retorted, “Who made you chief and ruler over us? Do you mean to kill me as you killed the Egyptian?” Moses was frightened, and thought: Then the matter is known!
(13) When he went out the next day, he found two Hebrews fighting; so he said to the offender, “Why do you strike your fellow?”: Because Moses tries to achieve justice in every situation he encounters, he again intervenes in this second, new conflict. But this time it turns out that his efforts are to no avail. And the reason for this is to be found in the Jews themselves.
(14) He retorted, “Who made you chief and ruler over us? Do you mean to kill me as you killed the Egyptian?”: Not only does he disobey Moses; he derisively rejects the very suggestion of establishing justice in this situation.
Moses was frightened, and thought: Then the matter is known!: This is usually understood to mean that it became known that Moses had killed the Egyptian overseer. But the word noda‘ can means both “known” and “understood.” The Midrash therefore reads this verse differently. “It was now clear to Moses why the Jews deserved to be enslaved. They were morally depraved, brawlers and informers totally incapable of appreciating that someone had come to their aid.” Thus, the Midrash believes that Moses, disillusioned with the Jewish people, now decided that it would be best to not have to deal with them at all.
Moses was frightened: Moses’ earlier worldview (“the Jews are downtrodden, but they are all essentially very fine people who only need to be defended in order to rise and stand on their feet”) has now begun to disintegrate, and his inner fears are aroused. In Moses’ plans for the advancement of mankind he must now find someone to rely on other than the Jewish people, who are not – as he previously believed – merely “disadvantaged by their enslavement.” This crisis has led to a radical change in Moses’ attitude.
 Similarly, Isaac was seized with terror (Genesis 27:33) when he learned that he had blessed Jacob instead of Esau. See Bible Dynamics on Genesis, §30.13.