I loved Philosopher Mom's series on Teresa of Avila's "interior mansions." For those of you who aren't familiar with it, St. Teresa wrote a famous book on spiritual growth (The Interior Castle) in which she described the soul as a castle in which God dwells at the very center. She describes the various mansions (rooms) that a soul inhabits as it works its way towards God. E.g. souls who linger in the first mansions have not rejected God, but are not praying frequently; souls in the second mansions have actively decided to seek God but are still vulnerable to falling back into their old selfish ways; etc.
Anyway, this is the best series of blog posts I've read in a while, and I highly recommend taking the time to at least scan it. Here's the link to all the posts in the category (they're all short). Read from the bottom up to start at the beginning.