Objection 1. It seems that all things are good by the divine goodness. For Augustine says (De Trin. viii), "This and that are good; take away this and that, and see good itself if thou canst; and so thou shalt see God, good not by any other good, but the good of every good." But everything is good by its own good; therefore everything is good by that very good which is God.
Objection 2. Further, as Boethius says (De Hebdom.), all things are called good, accordingly as they are directed to God, and this is by reason of the divine goodness; therefore all things are good by the divine goodness.
On the contrary, All things are good, inasmuch as they have being. But they are not called beings through the divine being, but through their own being; therefore all things are not good by the divine goodness, but by their own goodness.
I answer that, As regards relative things, we must admit extrinsic denomination; as, a thing is denominated "placed" from "place," and "measured" from "measure." But as regards absolute things opinions differ. Plato held the existence of separate ideas (84, 4) of all things, and that individuals were denominated by them as participating in the separate ideas; for instance, that Socrates is called man according to the separate idea of man. Now just as he laid down separate ideas of man and horse which he called absolute man and absolute horse, so likewise he laid down separate ideas of "being" and of "one," and these he called absolute being and absolute oneness; and by participation of these, everything was called "being" or "one"; and what was thus absolute being and absolute one, he said was the supreme good. And because good is convertible with being, as one is also; he called God the absolute good, from whom all things are called good by way of participation.
Although this opinion appears to be unreasonable in affirming separate ideas of natural things as subsisting of themselves--as Aristotle argues in many ways--still, it is absolutely true that there is first something which is essentially being and essentially good, which we call God, as appears from what is shown above (Question 2, Article 3), and Aristotle agrees with this. Hence from the first being, essentially such, and good, everything can be called good and a being, inasmuch as it participates in it by way of a certain assimilation which is far removed and defective; as appears from the above (Question 4, Article 3).
Everything is therefore called good from the divine goodness, as from the first exemplary effective and final principle of all goodness. Nevertheless, everything is called good by reason of the similitude of the divine goodness belonging to it, which is formally its own goodness, whereby it is denominated good. And so of all things there is one goodness, and yet many goodnesses.
This is a sufficient Reply to the Objections.
Source: Summa Theologica (New Advent)