Unlike commandment 8 which we looked at last week (don’t steal), adultery isn’t against the law. There are consequences of course, there always are if we step outside God’s commands, but we don’t end up in prison. So what’s the big deal?
Firstly, God is holy, and he wants his people to be holy too. That means they should exhibit sexual purity and not misuse his good gift. As we’ve seen recently, God has set the boundaries for sexual intimacy within, and only within, heterosexual marriage. So adultery, in broad terms, is having sexual relations with someone to whom you are not married. One person may be married to someone else, or both may be single. Either way, it comes under this catch-all statement of adultery. Elsewhere it’s called sexual immorality. And the Bible says it is wrong.
We also need to bear in mind the high standards Jesus sets on our moral conduct. According to Jesus, adultery doesn’t require physical contact. Jesus says that if we lust after someone to whom we are not married, it’s as if we have committed adultery with them in our hearts already. True holiness must begin in our minds. That’s why looking at porn or reading books that leave us lusting or longing for the affections of someone aren’t just unhelpful- but sinful.
But there’s a third facet too that is unique to those who are married. Under the Bible’s definition, marriage isn’t simply an agreement to live with one another and pool resources, it’s a solemn oath, a binding covenant, which is meant to last as long as both parties live. And since God is a God who always keeps his promises, so he expects his people to keep their promises as well. In good times and in bad, in times of plenty or times of poverty, when the grass looks greener, and when looks begin to fade. Many people find that hard, as Jesus’ disciples commented in Matt 19v10, but that’s the call. Married disciples of Jesus are to seek to live holy and faithful lives, keeping their wedding vows as God keeps his promises to us.
Unlike some other sins, sexual sins like adultery always have an impact on others. That’s why it’s so important to take this command to heart and do what it says.