What's the Name of That Book??? discussion

The characters realized that they were still on the earth because of different reasons, whether they didn’t believe in God or their sins and they think that their the only ones left on earth and it’s broken down into different first person stories and thoughts.
I read this series around 2006-2008, I just remember there being a lot of books in this same series. All of the titles I remember were similar to one another and that if you stacked them in order on top of each other the spine spelled something or made a picture.

I'm assuming we can rule out Left Behind?

Actually I think that’s exactly the book I was thinking of! Thanks!

Oh! 😄 You're welcome! I didn't know there were editions where the spines connected.