Heidelberg Catechism, Lord's Day 41, question 108. What does the Seventh Commandment teach us? That all unchastity is a curse of God, and that we should therefore loathe it with our whole heart and live chastely and modestly, whether in holy wedlock or in single life. Question 109. Does God forbid nothing more in this commandment than adultery and such gross sins? Since both our body and soul are temples of the Holy Ghost, it is His will that we keep both pure and holy. Therefore, He forbids all unchaste actions, gestures, words, thoughts, desires, and whatever may entice thereto. This is one of those commandments which is widely acknowledged to some degree, but which is also widely restricted in its application. Very few people really believe or really practice, really implement the full depth, the full rigor of this commandment, because it's not just about observable external things. It's not just about violations that would make even a worldly person gasp and turn pale. This is about the root, like all the commandments. This is about the root of the matter. This is about the heart. This is about where that kind of behavior comes from. And the Lord never teaches us to fight losing battles, the Lord never teaches us, well, wait until it gets to this level and then attack it, then resist it, then oppose it. The Lord is always directing us to root out sin from its first movement, not to let it get a foothold. And so when the seventh commandment says, thou shalt not commit adultery, we're not supposed to look at that and think, well, as long as I fall short of the technical definition of adultery, I'm okay. I can go right up to that line, and as long as I don't cross it, then I'm fine. That's not true. The reality is that adultery, like all sin, begins in the heart. And so we have to start there. We have to get to that point. We have to resist it there. You notice how the Heidelberg Catechism puts it. First of all, all unchastity is a curse of God. That's the negative side. But then it also gives us the positive side. Why should we be pure and holy? Why should we live chastely and modestly? Because our body and soul are temples of the Holy Ghost. That's the privilege. What are we losing by resisting adultery in its very first movement? Well, nothing worth mentioning. What we're doing is we're sanctifying the Holy Spirit's dwelling place. That is a tremendous privilege that the Holy Spirit dwells with us. It's not a privilege then that we want to disregard or treat lightly. We don't want to despise our birthright in that regard. Now, as I said, many people don't really agree or don't really understand with how strict and yet how blessed this commandment is. But it's not just the Heidelberg. The Westminster Shorter Catechism puts it this way. Question 71, what is required in the Seventh Commandment? The Seventh Commandment requireth the preservation of our own and our neighbor's chastity. Notice this in heart, speech, and behavior. Where does it start? It starts with the heart. And what is forbidden in the Seventh Commandment? The Seventh Commandment forbiddeth all unchaste thoughts, words, and actions. Where does the prohibition reach? It reaches to the inside. It reaches to the brain and the heart, not just to the outside. Well, may God give us grace in the power of the Holy Spirit and in light of the wonderful privileges that we have to turn away from all unchastity of every kind.