This is outstanding:
“The difference between the law and the gospel does not at all consist in this: that the one requires perfect doing, the other only sincere doing – but in this: that the one requires doing, the other, not doing but believing for life and salvation. Their terms are different, not only in degree, but in their whole nature.”
Quoted from Walter Marshall, The Gospel Mystery of Sanctification, 6.2. This book is one of those rare ones that takes your breath away even if you’ve read parts of it five or six times. It is probably one of the top 10 books I’ve read in the past few years. I very highly recommend it.