The Bible, in its many versions, is the book of faith for Christians. Many activists against body modification quote from the Bible, specifically from Leviticus 19:28, which reads “Ye shall not make any cuttings in your flesh for the dead, nor print any marks upon you: I am the LORD.” However, as Shannon points out in his article "Does God Hate Your Tattoos?" there are many verses in the Bible that support the idea of body modification.
The Bible, and other Christian symbols, are also sources that many people turn to for tattoo concepts. The design of the 'praying hands' has been used in western tattooing for decades.