Here’s a link to an article by Rabbi Daniel Lapin about how the OT prohibits the primitive rituals of self-mutilation
In the New Testament, too, Paul describes the body of a Christian as the temple of the Holy Spirit, so we should honor God with our bodies. It's the same passage where he says, "shall I take the members of Christ and unite them with a prostitute?" Back when I used to cut that was the passage they used against me. Self-destructive behavior is not condoned by God.
What this means regarding lots of saints' expression of faith by hurting themselves (like st. Rose of Lima or in my parish, Conchita, who founded the Missionaries of the Holy Spirit and branded Jesus' name on her chest) I don't know. I will say there is a probably a fundamental difference between pain for pain's sake and suffering in order to grow in faith.
Add to that, Pope John Paul II was said to have whipped himself with a leather belt or something.
St. Francis of Assisi rolled naked in the snow. Some saints threw themselves into a briar patch.
I think the verses about self-mutilation are referring to ritual mutilation.
These bizarre forms of self-torment are certainly not the norm for believers, even if you consider Jesus’ self sacrifice.
Our sacrifices are supposed to be spiritual, first of all.
The bible also prohibits us from getting tatoos .
That is one of the laws in the Old Testament that some people try to rationalize and say that it doesn't apply.
Exactly what part of tatooing the body which is the temple of the Holy Spirit glorifies God?