sin - a noun

I've been reading a book called Having a Mary Spirit by Joanna Weaver. She brought up the point that in the book of Romans sin is used as a noun each time except once. This was big for me as I always think of sin as a verb, something I did, or said or thought.

I can so relate to Paul in Romans 7 when he talks of not doing what he wants to do and doing what he does not want to do. This is a daily struggle for me. So when I thought about sin as a noun, an entity within, it made more sense.