1 Thessalonians 4:6-8

6and no one should ever violate or exploit his brother in this regard,1 because the Lord will avenge all such acts, as we have already told you and solemnly warned you. 7For God has not called us to impurity, but to holiness. 8Anyone, then, who rejects this command does not reject man but God, the very One who gives you His Holy Spirit.