God is the creator of sex. Part of his purpose in creating sex was for our pleasure. But God also set limits for the enjoyment of sex, for our protection. When we go outside those boundaries, we enter into sexual sin. These Scriptures are provided as an aid for those who wish to study what the Bible says about sexual sin.
1 Thessalonians 4:3–7
God's will is for you to be holy, so stay away from all sexual sin. Then each of you will control his own body and live in holiness and honor—not in lustful passion like the pagans who do not know God and his ways. Never harm or cheat a Christian brother in this matter by violating his wife, for the Lord avenges all such sins, as we have solemnly warned you before. God has called us to live holy lives, not impure lives.
Galatians 5:19
When you follow the desires of your sinful nature, the results are very clear: sexual immorality, impurity, lustful pleasures ...
Ephesians 4:19
Having lost all sensitivity, they have given themselves over to sensuality so as to indulge in every kind of impurity, with a continual lust for more.
Ephesians 5:3
Let there be no sexual immorality, impurity, or greed among you. Such sins have no place among God's people.