Aya number 15 of surat Al-Qasas

And he entered the city at a time of inattention by its people and found therein two men fighting: one from his faction and one from among his enemy. And the one from his faction called for help to him against the one from his enemy, so Moses struck him and [unintentionally] killed him. [Moses] said, "This is from the work of Satan. Indeed, he is a manifest, misleading enemy."