NET
24 When he saw one of them being hurt unfairly, Moses came to his defense and avenged the person who was mistreated by striking down the Egyptian.
Darby
24 and seeing a certain one wronged, he defended [him], and avenged him that was being oppressed, smiting the Egyptian.
KJV
24 And seeing one [of them] suffer wrong, he defended [him], and avenged him that was oppressed, and smote the Egyptian: