Lessons I learned:
1) Why do we follow and obey Christ? Our primary motive is not gratitude for what Christ did on the cross (although we are thankful nonetheless), but faith in God's future grace.
2) The faith that sanctifies is the same faith that justifies. We are called to obedience, not by our own works, but by faith.
3) Love towards others is a fruit of faith, i.e. "faith working through love" (Gal 5:6). True love for others can only come from a heart of faith.
4) The root of sin is unbelief, and therefore the battle against sin is a battle for faith, a battle to trust in the Lord and be satisfied in Him.
5) Lastly, though it was not a major theme of the book, I learned about the glorious hope of the resurrection in the last few chapters: not just a resurrection of our spirits, but of our bodies. God did not create our bodies just to get rid of them: he created them for His glory! What great future grace we have to look forward to!
I'm sure there are many other lessons as well. This book is so rich, so deep, and speaks straight from the Scriptures. If you cannot tell already, I highly recommend it.
eBook Future Grace