Who has read the summa theologiae of St. Thomas Aquinas?

I think that Aquinas is trying to argue that man is naturally meant to be good because we are in the image of God who is inherently good.In other words, people should be good so that they can live up to being made in the image of God. Everything that is made by God is good and strives to reach perfection because God is perfect. Sounds very circular, hope it helps.