Acts 7:23 in the King James Version
And when he was full forty years old, it came into his heart to visit his brethren the children of Israel.
Context
22 Moses was instructed in all the wisdom of the Egyptians. He was mighty in his words and works.
23 But when he was forty years old, it came into his heart to visit his brothers, the children of Israel.
24 Seeing one of them suffer wrong, he defended him and avenged him who was oppressed, striking the Egyptian.