After reviewing Dennis Ngien's chapter promoting divine passability, I engaged in some form of interaction with him (though that was not my idea and I did not initiate it). We left it cordially as a stalemate, but I left more convinced than ever that divine impassibility is indeed biblical. In this short post, I would like to show why the doctrine of divine impassibility is a necessary consequence in light of the doctrine of divine immutability. Therefore, a denial of the doctrine of divine impassibility should logically cause a denial of the doctrine of divine immutability as well (modus tollens). Of course, if divine immutability is denied, then God is no more God, as it would be shown later.
Divine impassibility is defined as saying that God does not have passions, not that God does not have emotions. By emotions, we mean the affections of God. By passions, we mean "the state of being acted upon or affected by something external" (dictionary.com). The difference between emotions and passions therefore lies in the fact that passions are reactions to something external. whereas emotions are merely affections (which are more generic in their scope).
In this light, if God is passible, that is to say that he has passions and thus reacts to external stimuli, then God in his internal affections experience change in time. If God truly experience change in se, even if it is merely in his affections, then He has changed in some small way or another in time. If God has changed in some way or another, no matter how small, then he is mutable by definition. Therefore, if God is passible, then He must be mutable.
Once one denies immutability, then the Pandora's Box is opened. If God is mutable, then why can't He change to become not God? If it is objected that certain divine attributes cannot be changed, upon what basis can we say that? If we say the Scriptures (which is true), then which passage should take precedence over another? The doctrine of divine passibility if embraced can only be proven from the narrative portions of Scripture. Therefore, with this precedent, what is there to stop us from interpreting anything predicated of God (that God does not repent cf Num. 23:19) and "clarify" it according to the narrative portions which show God "repenting" (ie. Deut. 9: 13-29)?
It must be here recognized that orthodox Christians have never denied that God has emotions. God is not the Hegelian Ideal Principle, or even the unknowable and impersonal Logos of the Greek philosophers. God after all is love (1 Jn. 4:16) and He genuinely loves His people. What makes God's emotions different from passions is that they are immutable and eternal. God is always love, and God always loves His people, even from eternity in electing us for His glory (Eph. 1:4-6). Likewise, God is always just, and therefore God's Moral Law can never change. God's wrath in this respect is His alien work, as an application of God's love expressed in hatred towards the violation of His justice as manifested in the Moral Law.
In conclusion, divine impassibility and divine immutabiity are linked. Deny one and you deny the other. Ngien is thus in error in denying divine impassibility.