All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Tattooing is forbidden by the Sharee'ah as it is a major sin regardless of what is tattooed even if it is the Shahaadah (the Testimony that None is worthy of worship but Allah and that Muhammad is His Slave and Messenger). It is narrated in a sound Hadeeth that the Prophet cursed the person who performs tattooing (to others) and the one who gets himself tattooed.” [Al Bukhari]
In fact, tattooing with the attributes of Allah, or His Names, or with the name of the Prophet is a greater sin as it is a kind of despising the status of these sacred names, as the person who has this tattoo goes to the bathroom and other impure places where such names and attributes should not be introduced.
For more benefit on tattoos and tattooing, please refer to Fataawa 89609, 104893, 266893, 85613, 89503, 84503 and 84562.
Allah knows best.