I know I struggled a long time with issues of sin, but with repentance and trying to overcome, yes with the blood of the lamb, eventually we get it right, and then He shows us the next thing to correct and so on.
Opinions on 666: The Mark of the Beast? When you think evil thoughts you disassociate and create an alter-ego.
This is the grace that those who want live under the law lose: Gal 5:1 Stand fast therefore in the liberty wherewith Christ hath made us free, and be not entangled again with the yoke of bondage.
Likewise, rather than being something literal such as a 666 tattoo, the mark of the beast symbolically identifies those who let the political system rule their lives.
The pagans wore tattoo pictures of their gods and also would have piercings and cut themselves.