Christopher Coates 
The Resurrection Wager [EPUB ebook] 

When two scientists develop the ability to go back in time, there is only one place for them to go to demonstrate their new technology.
After they make a wager about whether or not the resurrection of Jesus really happened, the two set out to prove their theories. They soon learn that there are others who are interested in their technology, but not for a scientific purpose.
But do they really understand the implications of their discovery – and what awaits them 2000 years in the past?