1 Corinthians 6:18
18 Run from sexual sin! No other sin so clearly affects the body as this one does. For sexual immorality is a sin against your own body.
1 Thessalonians 4:3-5
3 God’s will is for you to be holy, so stay away from all sexual sin. 4 Then each of you will control his own body and live in holiness and honor— 5 not in lustful passion like the pagans who do not know God and his ways.
4 Give honor to marriage, and remain faithful to one another in marriage. God will surely judge people who are immoral and those who commit adultery.
5 So put to death the sinful, earthly things lurking within you. Have nothing to do with sexual immorality, impurity, lust, and evil desires. Don’t be greedy, for a greedy person is an idolater, worshiping the things of this world.