Okay. I never OWNED a Christian bookstore, however I did work for a bookstore that was a member of the Christian Bookseller's Association.
Assuming you want to sell new and not used books, there are a few basic places you can get information:
American Booksellers Association
Whether you are buying/selling beca textbooks, bibles, or best sellers, there are some fundamentals to running a bookstore that won't change. The ABA used to have a prospective booksellers' school and a booksellers' school, I do not know if they offer either these days, as I haven't been a member for over 10 years.
For Christian bookselling, here's that association too, although it seems they've changed their name slighly:
CBA :: The Association for Christian Retail
The American Booksellers Association (first link above) used to have specialty directories available of their members. It wouldn't probably be profitable to open a new bookstore down the street from an established bookstore with an emphasis in religious books, probably. Find out what each of the two organizations have re opening a new bookstore.
Two or three things I can tell you for sure: 1) Selling new books is frequently a cash-flow business, you buy books for cash, you return books (or return stripped covers) for credit, and the credit is applied to the newest invoice, not the oldest. You have to be able to come up with the cash to pay that old bill.
Bibles and classics have a longer shelf life than other material, but even in religious books there is a time where the stock needs to be replaced/refurbished. Think about this and how you'll pay for it up front.
If your sales start out really well, don't count on them continuing that way. Plan for your worst case scenario, not the world is coming up roses.
I don't know if this is true for religious bookstores or not, but it IS true for general bookstores: 60% of annual sales occur between Black Friday and Christmas Eve. That's 60% of what you make for the YEAR.
IHTH!
Judi