A while back I posted some bits from Knowing God on the doctrine of divine judgment, or more precisely on Jesus as the Father's agent of judgment. Packer follows up this difficult subject with the equally difficult subject of wrath as an attribute of God. Like judgment, this is a subject many (myself included) would rather not face up to, but it's all throughout the Bible. The very writer, John, who tells us the wonderful news that God is love goes on in the next breath to speak of judgment (see 1 John 4), and it's his revelation on Patmos that provides us with images of God's wrath in action which boggle the mind.
Packer suggests that some believers feel the idea of wrath to be "unworthy of God". We have to understand that when Scripture uses anthropomorphic language such as the word "anger" to describe an attribute or action of God it does so leaving out the imperfections and sinfully mixed motives of human beings. The same is true of "love".
Thus, God's love, as the Bible views it, never leads him to foolish, impulsive, immoral actions in the way that its human counterpart too often leads us. And in the same way, God's wrath in the Bible is never the capricious, self-indulgent, irritable, morally ignoble thing that human anger so often is. It is, instead, a right and necessary reaction to objective moral evil. God is only angry where anger is called for. Even among humans, there is such a thing as righteous indignation, though it is, perhaps, rarely found. But all God's indignation is righteous.
What this means is that God's anger, or wrath, is never motivated by the things our anger often is -- wounded pride, cruelty, bad temper. God never "loses it". His motivations are always pure. His wrath is as much a part of his moral perfection as his love.
That being said, this doctrine has been much abused. Many folks have been turned off to the Christian message because of an unbalanced presentation of a wrathful God absent the good news of his mercy, grace and love. Wacko sects gleefully consigning people to hell should disgust followers of Jesus. Yet I believe Packer is correct that unless we reckon with the "solemn reality" of God's wrath we'll inevitably end up with a watered down gospel. I heartily recommend his classic treatment of these hard but foundational truths.
Quote from Knowing God (p. 151)