The Ninth Commandment: You shall not covet your neighbor's house.
The Tenth Commandment: You shall not covet your neighbor's wife or his workers or his animals or anything that belongs to your neighbor.
Both the Ninth and Tenth Commandments cover some common ground--in both of these commandments God forbids coveting: desiring what we shouldn't have or can't have. When God gives earthly or spiritual blessings to another person, he forbids us to desire what he has given that other person, whether house, spouse, or anything else.
But isn't it natural to desire what others already have? It certainly is. How can God forbid us to do what comes naturally? The Bible tells us that "The LORD knows the thoughts of man" (Psalm 94:11). God knows that human beings have a natural tendency to want to acquire what others possess. God also knows that such desires can lead to many sins. One of the Bible's best known sayings is "The love of money is a root of all kinds of evil" (1 Timothy 6:10). The sin of coveting can lead to many other sins, to sins forbidden in other of the Ten Commandments: stealing, adultery, even murder. Sinful human beings will stop at nothing to obtain what they desire, whether God forbids it or not.
Human beings are naturally sinful. By nature we desire and do what God forbids. Over the past few weeks we've looked at God's Ten Commandments. We've seen some examples of what God commands and forbids us to do, and we've seen that human beings by nature disobey God's commands. Every one of us has broken all of God's Ten Commandments in one way or another. Breaking even one of God's laws earns an eternity of punishment in hell. For us, who have broken all ten Commandments, the punishment we deserve is both unimaginable and unbearable.
In his law, God shows us that we deserve nothing but the worst punishment forever because of our sins. Yet in the Bible God also shows us that he has forgiven our sins. In a few weeks Christians will celebrate the birth of Jesus, our Savior. To save us from the punishment we deserve, Jesus came to take that punishment in our place. Jesus took our place in obeying God, keeping all his commands and laws perfectly. We are sinful, but Jesus was holy. We deserve punishment and death, but Jesus suffered our punishment and died in our place. Because Jesus took our place both in obedience and in suffering, God forgives our sins and promises us eternity in heaven rather than hell. God promises to bless us just as if we'd kept all his commands ourselves.
Jesus promised that he would return soon to this earth. During the Advent season we not only prepare to celebrate Jesus' birth, but we prepare our souls for the day he returns to take us to heaven. The Bible tells us how to prepare for that day: "Clothe yourselves with the Lord Jesus Christ, and do not think about how to gratify the desires of the sinful nature" (Romans 13:14).
As Christians who desire to thank God for saving us and who prepare for Jesus' return, we turn away from our sins. The Ten Commandments show us how. The Ten Commandments show us how to obey God and serve him with our lives. The Ninth and Tenth Commandments sum up the way God wants us to treat others. In his Small Catechism, Martin Luther explained what God tells us in these commandments: "We should fear and love God that we do not scheme to get our neighbor's inheritance or house or obtain it by false claims, but do all we can to help him keep it... We should fear and love God that we do not force or entice away from our neighbor his wife, workers or animals, but urge them to stay and do their duty."
As human beings we still have sinful desires, and we still desire to get for ourselves what other people already have. Christians resist sinful coveting and instead do their best to help those around them. Christians serve God rather than themselves, and reflect God's love and mercy in the way they treat others.