The body is not for immorality, but for the Lord; and the Lord is for the body…Do you not know that your bodies are members of Christ? Shall I then take away the members of Christ and make them members of a harlot? May it never be! Or do you not know that the one who joins himself to a harlot is one body with her?… Flee immorality. Every other sin that a man commits is outside the body, but the immoral man sins against his own body. (1 Corinthians 6:13,15,18).
For this you know with certainty, that no immoral or impure person or covetous man, who is an idolater, has an inheritance in the kingdom of Christ and God. (Ephesians 5:5).
For this is the will of God, your sanctification; that is, that you abstain from sexual immorality; that each of you know how to possess his own vessel in sanctification and honor, not in lustful passion, like the Gentiles who do not know God. (1 Thessalonians 4:3-5).
Let marriage be held in honor among all, and let the marriage bed be undefiled; for fornicators and adulterers God will judge. (Hebrews 13:4).