Why was the law given?

There are three misconceptions entertained about the law of God and its Ten Commandments:

1. Most people have a vague notion that the law was always in existence and that it must have been given to the first man, Adam, or soon after. Actually, God gave the law to Moses for Israel about 1500 B.C., after about 2500 years of human history had elapsed (John 1:17). So mankind lived on earth for about 2500 years without the law or the Ten Commandment.
2. Most people suppose that the law and the Ten Commandments were given to mankind in general, when in fact, it was given to Israel alone (Deuteronomy 5:2,3).
3. Most people suppose that the law and the Ten Commandments were given to help us be good. Even some pastors teach this, although the Bible clearly tells us they were given to show us we are guilty sinners.

It's true that the law, while given to Israel, also shows us that we are sinners. This is why Romans 3:19 says:

Now we know that whatever the law says it speaks to those who are under the law, so that every mouth may be stopped, and the whole world may be held accountable to God.

But most important of all, few people realize that the Lord Jesus Christ died for our sins to deliver us from the just condemnation of the law...

Christ redeemed us from the curse of the law by becoming a curse for us… (Gal 3:13).

For our sake he made him [Christ] to be sin who knew no sin, so that in him we might become the righteousness of God (2 Cor 5:21).

...so that believers are not under the law.

For sin will have no dominion over you, since you are not under law but under grace (Rom 6:14).