reading "Future Grace"

I'm in the process of reading "Future Grace" by John Piper, and it is blowing away my worldview.  I'm only about a third of the way through (it's a sizeable 397 pages) but I've already been staggered by the biblical truths he's been laying out.  I've also been surprised by how easy it has been to read; often reading Piper can be slow and heavy going, but this book is very accessible and readable.  

The message of the book can be summarized thus: we've gotten the motivation for our Christian life backwards.  We say we are saved by faith alone (rightly) and that our good works are works of gratitude.  But you will look in vain for any Biblical texts that explicitly tie gratitude to obedience.  Rather than trying to empower obedience by gratitude for past grace, we should look to faith in future grace for that power.  In other words, we need to bank on the promises of God.

For example: anxiety.  How are we supposed to defeat the sin of anxiety in our hearts?  The popular Christian response is that we should look back on all the times God has been faithful to us, and therefore not worry.  Now, that seems like great advice.  Of course, looking back on God's faithfulness and especially back to the cross is helpful and necessary, but only so far as it strengthens our faith for looking forward.  And more importantly, it's not how the Bible talks about dealing with anxiety.  The Bible says things like, "Don't be anxious...for my God will supply all your needs according to His riches in Christ Jesus. (Phil 4:19)"  "Don't be anxious... because all these things will be added to you as well. (Matt 6:33)"  "Don't be anxious... for no eye has seen a God beside you, who works for those who wait for Him. (Isaiah 64:4)"  "Don't be anxious... for all things work together for good for those who love God. (Rom 8:28)"  Take hold of the promises-- that's where the power to fight sin is found.

The back cover of the book puts it well: "No one sins out of duty.  We sin because we want to.  Sin promises happiness, and we buy the lie.  So how can the root of sin be severed in our lives?  The penalty of sin must be paid by the righteous blood of Christ.  And the power of sin must be broken by banking on the promises of God."

Good stuff.  I've always struggled (and I suspect I'm not alone here) in figuring out how the "good works" of the Christian life tie into the truth that we are saved "by faith alone."  Luther's thing on gratitude seemed to make sense in my head, but not in Scripture.  This book is helping me put them together, and it's revolutionizing everything in the process.  I highly recommend it.