If you're interested in reading something along the line of thrillers based on a religious context then you might want to read: The Last Cato. Its actually a translation from a Spanish novel by Maltide Asensi. The book uncovers a path to Stauroflakes, an ancient secret brotherhood associated with protecting the Holy Cross.
There's also The Expected One by Kathleen McGowan. The main lead sets on a journey to find some lost religious scrolls from the time of Christ. This book is the first in a series of three books. The second one is already out so if McGowan's writing is to your liking, you might enjoy reading the second one too.
James Rollins' Map of Bones is a fun book too! This one is again about an ancient secret society and a treasure hunt carried out through the novel. Rollins' writes some great thrillers.