Recently my wife bought me a guitar for my birthday. A very nice guitar. I was grateful. Still am. But not so much because now I have this kind of guitar. More because now and 'till death us do part' I have this kind of wife. I'm grateful to have the gift. But what really thrills me is to have the giver.
Ask a typical evangelical why Christians do good works and they'll say "Out of gratitude for what God's done." You know the drill: He's given me heaven, the least I could do was tithe.
And apparently this is all of grace because it's a response to a gift.
But it's a quite detached response to a quite detached gift. God gives me stuff and I am moved to give stuff back.
But isn't it more that God gives me Himself since He gives me Christ. And all good things are in Him. There's a lot of stuff in there. Eternal life, wrath averted, forgiveness of sins, a spotless righteousness, a new spiritual family... lots to be grateful for. But really what I have is Christ. And in Him I don't simply have a lot of great stuff. Rather what I have is this God - the God who is a Giver.
The magnitude of His gifts are not finally what call forth my grateful response. It's the fact that I have such a Generous Giver - not simply as a Benefactor to draw upon. But He Himself is mine.
Not only His gifts belong to me, but the Giving God belongs to me. Therefore my response will not be payback but instead it will be my Christ continuing His generosity through me. The Gift that keeps on giving.