Material with its inherent properties and nature can only possess reality and character if it is formalised. We cannot understand material unless it is in relation to the outcome of production.
In this way does a teleological explanation of material come to be.
It should be noted the teleological explanation authored by Aristotle, upon which Medieval Christian doctrine was established, makes no room for artistic intention. There is no agency within the Aristotelian cosmology, and the cosmos was self sufficient.
The difference between the Medieval/Thomistic understanding of material, and the Greek/Aristotelian understanding of material, is that God calls forth the form from the material in the former whilst the latter sees form spring from the nature of material itself.
The medieval understanding does not discard the Greek notions, however. The medieval mind saw God directing material from within its own nature and natural tendency. Even though God is strongly articulated, he is not removed from creation. Creation holds within it the finality of God; finality is immanent.