Acts 7:22-24
7:22 So Moses was trained in all the wisdom of the Egyptians and was powerful in his words and deeds.
7:23 But when he was about forty years old, it entered his mind to visit his fellow countrymen the Israelites.
7:24 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.