There is only one mention of tattoos in the Bible, which occurs in the Old Testament. Leviticus chapter 19 verse 28 states, "You shall not make any cuttings in your flesh for the dead, nor tattoo any marks on you: I am the Lord."
There is some debate among biblical scholars as to what this passage actually means, but it is generally thought that it referred to the common pagan practice of cutting and tattooing the bodies of people who were mourning the death of a loved one.
This command was given by God to the tribe of Israel, which is why Judaism forbids tattooing. However, the command was meant to separate the Israelites from their pagan neighbors, so many Christian scholars believe that it only applies to Jews and not to Christians.
However, there are others who point to passages in the book of 1 Corinthians, which mention the body as a temple to God that must be taken special care of in order to glorify His name. Some Christians have taken this to mean that the body must be remain pure and unaltered, meaning that it should never be tattooed or changed in any way. Despite this, there is still much debate as to whether the Bible specifically prohibits Christians from getting tattooed.