Or HaChaim on Exodus 2:13/אור החיים על שמות ב׳:י״ג

1 ?ויאמר לרשע למה חכה רעך He said to the wicked one: "why are you about to strike your companion?" Moses addressed the one of the two who was clearly wicked. He referred to the victim as "your companion," because if the victim were as wicked as the attacker why would the attacker want to strike him, seeing they were birds of a feather. Alternatively, Moses recognised that he dealt with one righteous and one wicked Israelite. This is why he challenged the attacker saying: "why are you about to strike a righteous person, someone who has not done you any harm?" He called the righteous person רעך, i.e. he relates to you like a friend. Although the Torah described the two as apparently on the same moral level when it says שני אנשים נצים, "two quarrelling people," it will be found that one of them started the fight because he was wicked, whereas the other continued the quarrel without compelling cause.