Don't have sex before marriage! applied to elite members of the church whose sexual sins were kept forever on the down-low. engaged in oral sex, Skype sex and mutual masturbation; saw each other completely naked. To engage in premarital or extramarital sex, before or outside of marriage, is to sin in God's sight. That is precisely the point of Hebrews , a verse often. Is Sex before Marriage a Sin? God loves sex. He really LOVES sex. He created sex and declared it, “good.”. question of oral sex. The question is always the same: Pastor John, is this practice permissible in a Christian marriage, or is it always sinful?