First, because matter is in potentiality. But we have shown (Q. 2, A. 3)
that God is pure act, without any potentiality. Hence it is
impossible that God should be composed of matter and form. Secondly,
because everything composed of matter and form owes its perfection and
goodness to its form; therefore its goodness is participated, inasmuch
as matter participates the form. Now the first good and the
best--viz. God--is not a participated good, because the essential
good is prior to the participated good. Hence it is impossible that
God should be composed of matter and form. Thirdly, because every
agent acts by its form; hence the manner in which it has its form is
the manner in which it is an agent. Therefore whatever is primarily
and essentially an agent must be primarily and essentially form. Now
God is the first agent, since He is the first efficient cause. He is
therefore of His essence a form; and not composed of matter and form.

Reply Obj. 1: A soul is attributed to God because His acts
resemble the acts of a soul; for, that we will anything, is due to our
soul. Hence what is pleasing to His will is said to be pleasing to His
soul.

Reply Obj. 2: Anger and the like are attributed to God on
account of a similitude of effect. Thus, because to punish is properly
the act of an angry man, God's punishment is metaphorically spoken of
as His anger.

Reply Obj. 3: Forms which can be received in matter are
individualized by matter, which cannot be in another as in a subject
since it is the first underlying subject; although form of itself,
unless something else prevents it, can be received by many. But that
form which cannot be received in matter, but is self-subsisting, is