[Note: I realized after preaching this sermon that I was a bit unclear at one point. In commenting on sex outside of marriage, I said something along the lines that extramarital sex does not bring two people into a "one-flesh" union. To be more specific, extramarital sex does not bring two people into a marriage union. 1 Corinthians 6:16 tells us that sexual activity does bring two people into a “one body” union in some sense, whether they realize it or not. Even sex with a prostitute does this, which is the most casual sexual exchange possible. But the physical union in sex outside of marriage is not sanctioned by God, nor does it by default constitute a covenantal union in the same way marriage does. Marriage goes beyond a merely physical (sexual) union because God Himself joins a man and woman together in a way that only He can (Matthew 19:6), forming a comprehensive "one-flesh" union that should result in one fully shared life. That's the reason that a man and a woman in the covenant of marriage should not hold back anything from one another. I hope that clears things up!]