Summa Theologica

This treatise deals in greater detail with the creation of the material universe as described in the Book of Genesis. 

All material created things are essentially good and lead us to God. Any evil that seems to be part of them is not in their essential nature, but is the result of wrong use. The entire universe is created and ordered to show forth the glory and goodness of God. The being of every individual creature represents God’s divine being.

Aquinas argues against the notion that God created things through the angels as intermediaries. Rather, God created all corporeal things by his immediate power. Although God is one, the things he created have diversity, which contributes to the perfection of the universe as a whole. 

Aquinas examines how God created the various parts of the universe and distinguished them from each other. The main points are:

1.  There was no point at which matter was utterly formless, but scripture describes ways in which creation in the beginning was formless in the sense of lacking beauty and light.

2.  There are two different types of prime matter: that which forms the heavenly bodies (incorruptible) and that which forms the earth (corruptible).

3.  The empyrean heaven (the highest part of heaven, where the blessed dwell) existed from the beginning of creation.