Morally Doubtful?

If He fulfilled not justice, I must; if He underwent not wrath, I must to eternity

-Owen

I've begun reading one of the books I recently got, In My Place Condemned He Stood, by Packer and Dever and I've been quite impressed by it so far. I'm hoping that reading this book will not only give me a greater understanding of the love and justice of God revealed in our Lord's Passion but that it will also inspire some blog posts. For now I'll just give a couple of quotes from the first chapter by J.I. Packer which especially impressed me:

The wrath of God is as personal, and as potent, as his love; and, just as the blood-shedding of the Lord Jesus was the direct manifesting of his Father's love toward us, so it was the direct averting of his Father's wrath against us.

So far from the manifestation of God's wrath in punishing sin being morally doubtful, the thing that would be morally doubtful would be for him not to show his wrath in this way. God is not just - that is, he does not act in the way that is right, he does not do what is proper to a judge - unless he inflicts upon all sin and wrongdoing the penalty it deserves.