Tafsir of Al-Qasas 28:14

{And he became established (wa-istawā)}: He became balanced, his maturity was perfected, and he reached the stage beyond which there is no increase.

As Laqīṭ said: “They bore your affair for the sake of God—may your mother be bereaved of you!— With a firm resolve, neither too young nor too old.”

This is forty years. It is narrated that no prophet was sent except at the age of forty.

{Knowledge (al-ʿilm)}: The Torah.

{And wisdom (al-ḥukm)}: The Sunnah. The wisdom of the prophets is their Sunnah. God Almighty said: "And remember what is recited in your houses of the verses of God and the wisdom" (Al-Aḥzāb: 34).

It is also said: Its meaning is that We gave him the conduct of the wise scholars and their demeanor before his mission, such that he would not perform any action for which he could be deemed ignorant.

{And he entered the city at a time of inattention by its people, and he found therein two men fighting: one from his faction and one from his enemy. So the one from his faction called for help against the one from his enemy. So Moses struck him with his fist and killed him. He said, "This is from the work of Satan; indeed, he is a manifest, misleading enemy." He said, "My Lord, indeed I have wronged myself, so forgive me." So He forgave him; indeed, He is the Forgiving, the Merciful. He said, "My Lord, for the favor You have bestowed upon me, I will never be an assistant to the criminals."}