You shall not make any cuttings in your flesh for the dead, nor print any marks on you: I am the LORD. [Leviticus 19:28]
From those passage in Leviticus it is pretty straight forward the prohibition of tattoos for any reasons including religious. Also bear in mind Deuteronomy 12:29-32 clearly forbids pagan religious acts from being used to honor God as well as biblical use of engraved images in worshipping God. I fail to understand why is it symbol like cross which has pagan origin are used by Christians as part for their devotion and worship.
Here in Cairo Egypt, Coptic christians get their bodies tattooed for Jesus even their youngs.
I would love to hear how other christians feel about this centuries old tradition.