Let me conclude with a few points of application.
My basic contention has been this - God's glory is His grace. The Trinity's overflowing life of other-centred love is the glory that shines out of all He is and does. It therefore makes no sense to think of His glory in self-centred terms.
But having said that, let me affirm something vitally important from Scripture. Once we're clear that God's glory is His grace, we should also say that there's a significant sense in which God acts for the sake of this glory and not for our sake.
Didn't I just say that God's glory is His other-centredness? Indeed.
And therefore if God acts gloriously won't that mean acting other-centredly? That's right.
Then how can I say that the triune God acts for this glory and not for our own sake? Well think of John 10:17-18. Jesus says "I lay down my life." And then He says "No-one takes it from me." It's really important to hold onto both. It is His eternal glory to lay down His life (v17 is amazing!). And yet all this happens at His initiative. He really and truly becomes a Victim - the Victim. But no-one makes Him a Victim but He Himself. This is truly an offering not a wage. Truly a gift and not a pay-off. It's the Saviour's push not the sinner's pull that's driving things.
And that's so important because one of the things John Piper is so keen to fight is our natural self-centredness. And it's absolutely right that we resist human narcicism. We'd love to think that Christ's an old softy who can't help himself when he sees a damsel in distress like us. We'd love heaven to confirm our own assessment of worth and be as besotted with us as we are. But the God of Scripture reminds us that His lavish other-centredness is not because we've twisted His arm (see my post on Ezekiel 36:16-32).
Let me put it in these two sentences - the first resists Piper's definition of glory, the second upholds his desire to fight narcisism:
The triune God acts for the sake of His gracious glory - not the glory of His self-centred, self-regard.
The triune God acts for the sake of His gracious glory - not for the sake of our self-centred, self-regard.
Essentially I'm saying it's right to oppose our human narcicism. But we don't do that by positing heavenly narcisism. Instead we proclaim the heavenly other-centredness of God which is not a confirmation of our self-obsession but liberation from it.
As an illustration I can't do better than Craig's story of modern day chivalry (thanks Craig). He was once walking down a corridor and as he neared the door he noticed a woman behind him. So - being the benevolent, other-centred guy he is - he opened the door and let her through. Apparently she scowled and said "I hope you're not opening the door for me because I'm a lady." Craig replied "No, I'm opening the door because I'm a gentleman."
That's what I'm talking about.
This act of grace was not motivated first and foremost by what was in the recipient. It was motivated by what was in the giver. The giver desired to be this kind of giver, in many ways regardless of the recipient. But he still determined to be giver.
In the same way the triune God acts in creation and redemption first and foremost "because he's a gentleman" not "because we're a damsel in distress." And so, at bottom, the Father loves us not because of anything in us but because He is Father.
So we see that all of this glory talk is just another way of upholding sola gratia (grace alone). But that's only natural because God's grace is His glory.
I am finding more and more ways of applying this kind of thinking pastorally.
Think of the parent faced with a manipulative child. On the one hand they might go soft and cave into the child. On the other they might harden themselves to the childs demands. But motivated by the glory of grace another way is opened for them. There is a way of loving the child in an even more costly way that counters their self-absorption.
Think of the nagging wife of Proverbs. A dead-eyed husband might say "Yes dear" and confirm her in her manipulative ways. On the other hand he might cut her down to size and fail to be her lover. Or, motivated by the glory of grace, he can seek ways of leading in love that resist her manipulation but that actually call on more love from him, not less.
Think of the "pull" someone exerts in a pastoral counselling situation (see here for Larry Crabb's thoughts on "pull"). How do we resist manipulative demands people put on us (which won't ultimately help them) without retreating from them? How do we love without loving being 'caving'?
I don't have all the answers but I do believe that as we meditate more on the LORD Christ's fierce determination to be Lover we will be able to pass on such love.
So in conclusion, Piper is right to oppose human self-centredness. But we mustn't do that by proclaiming a divine self-centredness. We will be truly released from self in the glorious other-centred love of our God: Father, Son and Holy Spirit.