Getting a distributor can help you get your book on the shelves of national chains and independent book stores. There are general book distributors, but a better choice for a Christian-themed book might be one of the Christian book distributors.
Christian book distributors specialize in representing Christian books, they work primarily with Christian book stores and understand the market in a way that a general distributor may not.
Whether you choose to work with a general distributor or a Christian book distributor, the process is much the same. They will want to see that you have a marketing plan, that there is a market for the book, and that the book is quality. That means an attractive, effective cover, the text is well-written and edited, and the interior design is professional.
If you wish to work with a Christian book distributor, two of the largest and best-known are:
Spring Arbor Distributors Inc.
An Ingram Book Group Company
BelieversPress offers a simple and affordable distribution program for small and individual authors/publishers (in partnership with STL).