Exodus 20:17

In the tenth, then, God made a law not only against evil things but against the desire for evil things. That is what makes it so death-dealing for an awakened conscience. In keeping with this, the Lord Jesus moved the weight of the law against both murder and adultery. He moved it from the act to the desire and impulse that prompts the act. He did this when He gave His Sermon on the Mount, reported in Matthew 5.

To covet is to crave something that another person has. You may never steal from him, yet the craving for what he owns is itself sin.

The real aim of giving the law was to bring to light what was in His people's hearts. That is why the commandment takes the form of a prohibition. Why else would it say, You shall not murder, You shall not commit adultery, You shall not steal, You shall not covet — unless the tendency to all these forms of sin was in them?

It is a sin that is never satisfied. It grows by what it feeds on. It leads to all sorts of other sins. It is the one sin of the heart that the ten commandments forbid outright — a hidden, secret sin that comes out of the heart. It leads to injustice and oppression, and to turning away from the faith. God hates it. It shuts people out of the kingdom of God, and it ranks with sins like theft, idolatry, and adultery. Yet this sin is so deceitful that few see how dangerous and awful it is. The world hardly counts it a sin at all. So a worldly Christian finds it hard to see that coveting what belongs to someone else is as bad before God as theft or drunkenness.

Covetousness involves no dishonesty. It is not even hard or sharp dealing. It is no more than the desire for more — the very spring of modern effort, the motive of bettering oneself, recommended to everyone from the mechanic to the millionaire. So the creature becomes the object, not God. That is why covetousness is called idolatry. It is man looking down, not up in dependence on God.

He does not say that he would have had no coveting. He says only that he had not known it. The craving was there, but he was in the dark about it. Then the law, like a lamp from God, shone into the dark rooms of his heart and showed the evil that was there. It is like a man in a dark room. Dust and mess may be all around him, but the darkness hides it. Let the sunbeams shine in, and he sees it at once. Do the sunbeams create the dust? Surely not. The dust is there, and they only detect and reveal it.

We cannot get rid of this covetous attitude unless the Lord Jesus works in our hearts by new birth. He makes us willing to judge our motives and to seek to live by wholehearted faith. Then, instead of envying others, we shall know how to "rejoice with those who rejoice, weep with those who weep" with no thought of ourselves. We shall be glad when others are blessed, even when we go without. That will not be because the law commands us not to covet, but because the grace of God is working in our hearts.