Years ago, I wrote a book on sin. To estimate its breadth and depth, I studied biblical and theological sources. But as much as the standard sources taught me, I was surprised to discover that I could also learn a lot about sin and grace by reading storytellers, biographers, poets and journalists.
Back in the mid-1990s I wrote a book on sin. Each of us knows sin experientially, of course, but few of us know it comprehensively even in that way because we are parochial even in our sinning. So I had to study sin. For a couple of years I read about sin in the Bible. I read commentaries on the Bible, theological encyclopedia articles and books on virtue and vice.