John Chrysostom

And to show this, he has added, "If we believe not, He abideth faithful: He cannot deny Himself": that is, if we believe not that He rose again, He is not injured by it. He is faithful and unshaken, whether we say so or not. If then He is not at all injured by our denying Him, it is for nothing else than for our benefit that He desires our confession. For He abideth the same, whether we deny Him or not. He cannot deny Himself, that is, His own Being. We may say that He is not; though such is not the fact. It is not in His nature, it is not possible for Him not to be, that is, to go into nonentity. His subsistence always abides, always is. Let us not therefore be so affected, as if we could gratify or could injure Him. But lest any one should think that Timothy needed this advice...