Summa contra Gentiles1.74 Chapter LXXIV. That the principal object of God's will is the divine essence

It is also evident from the foregoing that the principal object of God's will is His essence.

For the good understood is the object of the will, as proved above. Now the principal object of God's intellect is the divine essence, as we have already proved. Therefore the divine essence is the principal object of the divine will.

Again. The appetible object is compared to the appetite as mover to the thing moved, as we have stated above. It is the same with the thing willed in relation to the will, since the will belongs to the genus of appetitive powers. Wherefore if something besides God's essence were t!he principal object of God's will, it would follow that something else is superior to, and moves the divine will: and the contrary of this was proved above.

Further. The principal thing willed is to every wilier the cause of his willing: for when we say: wish to walk that I may be healed, we consider that we are stating the reason, and if it be asked, Why do you wish to be healed? we shall continue to give reasons until we come to the last end which is the principal thing willed, and is of itself the cause of willing. Accordingly if God wills principally something other than Himself, it follows that something other than Himself is the cause of His willing. But His willing is His being, as we have shown. Therefore something else will be the cause of His being: and this is contrary to the notion of the first being.

Again. To every wilier the thing willed principally is his last end: because the end is willed by reason of itself, and other things come to be willed by reason of it. Now God is the last end, because He is the sovereign good, as was proved. Therefore He is the principal object of His will.

Moreover. Every power is proportionate to its principal object according to equality: for the power of a thing is measured according to its object, as the Philosopher says (t Cceli et Mundi). Therefore the will is proportionate according to equality to its principal object, as well as the intellect and the senses. Now nothing is proportionate according to equality to God's will, except His essence. Therefore the principal object of the divine will is the divine essence. A'nd since the divine essence is God's act of understanding and whatsoever else is said to be in God, it is also clear that in the same way God wills principally, to will, to understand, to be one and so forth.