Introduction
This translation and analysis cover the commentary of Rabbi Ovadia Sforno on the interaction between Moshe and the Hebrew men who confronted him. The central question is why Moshe fled rather than punishing the man who indirectly or directly became a “moser” or informer against him to Pharaoh.
The Incident as described by Shmot / Exodus 2:11-15
It was in those days when Moshe was grown that he [began] to go out to his brethren, and he saw their burdens [hard labor]. [One day] he saw an Egyptian beating one of his Hebrew brethren.
He [Moshe] looked all around and [when] he saw that no man was there [watching], he killed the Egyptian and hid his body in the sand.
He went out the next day, and behold two Hebrew men were quarreling. And he said to the wicked one, “Why are you beating your friend?”
He [the wicked one] said, “Who made you a man, officer and judge over us? Do you intend to kill me as you killed the Egyptian?” Moshe was frightened, and he said, “So the matter is known.”
Pharaoh heard about the matter, and he planned to kill Moshe. Moshe fled from Pharaoh, and resided in the land of Midian, and he sat [lived] near the well.
Sforno on Exodus 2:11–14
Verse 11: “And he saw their burdens…”
He set his heart to see the affliction of his brothers.
“And he saw an Egyptian man beating a Hebrew man, one of his brothers…”
Out of a sense of brotherhood, he was moved to take vengeance [on the Egyptian].
Verse 13: “And he said to the wicked one…”
Because each of them [the two Hebrews] was his brother, he was not moved to take vengeance, but rather rebuked [him] with fairness.
Verse 14: “Do you intend to kill me?”
You are stirring up strife in order to kill me.
“And Moshe was frightened…”
Therefore, he guarded his life and fled.
“And he said, ‘So the matter is known’…”
[He said this] when this informer spoke these words of his in front of many people. Therefore, he did not kill the informer, for there was no benefit in killing him once the information had already been delivered/shared.

And this is ruled as Halachah by Shulchan Aruch, Choshen Mishpat, Laws of One Who Destroys Another’s Property Directly, and Informers and Talebearers, Siman 388, Se’if 11:
Se’if 11: If the informer carried out what he planned and informed, it is forbidden to kill him; but if he is established as a habitual informer, then he may be killed lest he inform on others.
Editor’s comment: The halacha described above is a reference to the Moser / Informer who endangers fellow Jews.
Appendix: Biography of the Sforno (based on the Bar-Ilan Responsa Database)
Rabbi Ovadia ben Jacob Sforno was born around the year 1480 (5240 in the Hebrew calendar) in Italy. In addition to all areas of Torah study, he studied medicine and other sciences. He settled in Bologna, where he practiced medicine, studied and taught Torah, engaged in communal needs, served as a judge, and even established a yeshiva and headed it. He passed away around the year 1550 (5310). Rabbi Ovadia wrote many books, most famously known for his commentaries on the Torah and parts of the Prophets. His approach to interpreting Scripture is along the plain meaning (peshat), based on the words of the Sages (Chazal), with expansions on matters of ethics and proper conduct. In philosophical matters, he followed the Rambam (Maimonides). His commentary on the Torah was first printed in Venice in 1567 (5327). The version in the database is based on the ‘Mishor’ edition, Bnei Brak 2002 (5762).