Obviously, a tattoo of a cross is “better” than a tattoo of a flaming skull, naked woman, or demon. Having a tattoo saying “Jesus saves” could indeed be a conversation starter with some people who would never approach a preacher wearing a suit and tie. Some refer to Revelation 19:16 as an example of Jesus possibly having a tattoo on His thigh, “King of kings and Lord of lords.”
The short answer is…nothing. At least nothing definitive. The Bible makes no specific reference to tattoos as we understand them in modern times. Some Christians condemn all tattooing as immoral because God clearly forbids them in Leviticus 19:28. Since the word tattoo does appear in this verse in some popular English translations, this argument seems straightforward. For example, the NIV reads, “Do not cut your bodies for the dead or put tattoo marks on yourselves. I am the Lord.”
The question is not necessarily “is getting a tattoo a sin?” The question is more “is getting a tattoo a good and necessary thing to do?” First Corinthians 10:23 declares, “Everything is permissible – but not everything is beneficial. Everything is permissible – but not everything is constructive.” Christian tattoos may be “permissible,” but are they beneficial and constructive?