If you take a look at the book of Exodus, the 10 commandments are never referred to by the Bible as the "10 commandments." Early Bible scholars counted 10 rules to follow in a succession and then thought of them as a set of 10 rules that God commanded Israelites, and consequently us, to follow.
However, to think of the 10 commandments as just 10 concrete rules can actually be limiting. That's because one aspect of the decalogue is that it's incomplete in scope. Sure it tells us to rest on the sabbath and not to commit murder or steal, but the 10 commandments tell us nothing about why we are to abstain from drugs, at least if we limit it to simply just a set of 10 rules.
When looking at the 10 commandments, there are not just 10 rules. There is also just one rule, and that is stated at the very beginning of the decalogue -- "I am the Lord your God, who brought you out of Egypt, out of the land of slavery. You shall have no other gods before me."
Every commandment after the first is simply an example of the first, which is about idolatry. To have other gods before the true God is the worst sin, in a sense, because it is the only sin that is expressed in scripture. The one and only sin we commit throughout our lives is to have idols.
When we commit adultery, we turn sexual pleasure into an idol that satisfies us more than God. When we steal, we turn material wealth into an idol that gives security apart from God. When we covet our neighbor's wife and belongings we look to our own ideals as our gods and worship them instead of the one true and living God.
The one and only sin that has abhorred the holy nature of God from the beginning of time is idolatry. I'm not just talking about asherah poles, golden calves and Baal. Figures for pagan worship are not the only idols. Every sin is connected to a form of idolatry.
We must remember that the asherah poles, for instance, were meant for good. They were figures that God commanded Moses to make as a sign of God's healing power. What happened after God made a miracle happen through these mediums of His grace and healing? The Israelites started worshipping the mediums instead of the source.
When we realize that every sin is a corresponding form of idolatry, we see the true way to freedom. Freedom does not come by saying no to stealing, coveting, lying or any other surface problem, but by acknowledging the root, which is idolatry, and understanding how these gods cannot answer our needs the way the one true God can.
God is the only God we serve, and to have other gods before Him is the root of all sin.
