In a previous post, I wrote:
Thomas, in question 3 of the Summa, adumbrates the simplicity of God: that God’s existence is his essence, and that God has no (non-metaphorical) predicate that is not also his essence. If we can say “God is good,” for example, then it is necessarily true that God is goodness. So also for “one,” “beautiful,” “real,” etc.
Now given the doctrine of divine simplicity, the same move can be made with respect to anger. That is, if God is angry, then it necessarily follows that God is anger itself.
From here it follows that if God is not anger itself, then it is not the case that God is angry.
Now I’ve never known of a theologian willing to claim that God is anger itself. And there are many reasons for this, not least that this would “reify” or “hypostasize” anger, giving it an ultimate, uncreated ontological status completely independent of the Fall (of man & angels).
But do you see what’s going on? Since we know that it is not the case that God is anger itself, it necessarily follows that God is not angry.
Does Scripture (and the liturgy) speak of “the wrath of God?” Yes, it does. However, it is important to keep that strain of thought in its proper (marginal) place. It is true only in a distant and radically derivative sense. (I need to think more about this.)
One last note: notice that all of this presupposes the simplicity of God. In other words, it assumes the classical doctrine about God that, in particular, he is in no way subject to temporality (pace the likes of that “open theist” Greg Boyd and that “process theologian” Alfred North Whitehead and all their respective followers), which is wholly and completely a created thing. Otherwise, this line of thinking, which demonstrates that God is not angry, fails.