1 Corinthians 6:17-19

But the one who is united and joined to the Lord is one spirit with Him. Run away from sexual immorality [in any form, whether thought or behavior, whether visual or written]. Every other sin that a man commits is outside the body, but the one who is sexually immoral sins against his own body. Do you not know that your body is a temple of the Holy Spirit who is within you, whom you have [received as a gift] from God, and that you are not your own [property]?