If you want to write theology, revision is in order.
I have page proofs from the publisher for my book Being Promised: Theology, Gift, Practice, so I think I can look back at the drafts.
Here's the lowdown:
Revisions of each of the five chapters:
chapter 1: 5 drafts
chapter 2: 10 drafts
chapter 3: 13 drafts
chapter 4: 6 drafts
chapter 5: 10 drafts
After putting it into one whole book: 10 more drafts.
Size of file that contains paragraphs and sentences eliminated: 301kb.
Revise, revise, revise.