Deuteronomy 5:1-3 (New Century Version)
1 Moses called all the people of Israel together and said: Listen, Israel, to the commands and laws I am giving you today. Learn them and obey them carefully.2 The Lord our God made an Agreement with us at Mount Sinai.3 He did not make this Agreement with our ancestors, but he made it with us, with all of us who are alive here today.
Hebrews 10:3-4 (New International Reader's Version)
3 But those offerings remind people of their sins every year. 4 It isn't possible for the blood of bulls and goats to take away sins.
Romans 10:3-4 (New International Reader's Version)
3 They(Israel) didn't know how God makes people right with himself. They tried to get right with God in their own way. They didn't do it in God's way.
4 Christ has completed the law. So now everyone who believes can be right with God.
How do we know that we have done something wrong and sinned against God? Part of the answer is that God through His Holy Spirit convicts us when we do wrong. But the other part of the answer is that since God chose the Jewish people as His path in which he would bring reconciliation of mankind and Himself, we have had the Law of Moses, the Ten Commandments and various other laws and decrees from God found in Leviticus and Deuteronomy of the Bible, that shows us what is expected for us to be obedient to a just and Holy God.
Take the time to read these two books and you will find a the laws that governed every aspect of daily life, and the penalties that were required if one disobeyed them. The Law of Moses also provided the instructions of what must be done to obtain atonement and forgiveness from God, and it pointed to a system so complicated that it was almost impossible to keep. In the generations that followed, the Jewish people often fell away from obeying God and began to worship other gods.
I believe that the real purpose of the law was to show us the impossibility of keeping it. Jesus even took it a step further when he told us that looking upon someone in a lustful manner was the same as commiting adultrey(Matthew 5:27-28 NCV), and being angry with someone was the same as murder(Matthew 5:21-22 NCV).
As I have stated before, no matter what we try to do in our own efforts, we cannot be reconciled or forgiven by a righteous and Holy God. He is the One who draws us to Himself and He is the One who provides the way to reconciliation and salvation. We will continue along that path over the next few days.