I was listing to a message from Steve Furtick today and he pointed out something amazing that I had never seen before. The link to the message is here and the action starts at the 5:50 mark...
In Exodus 32, Moses goes up on the mountain and comes back down with the laws of God written upon stone tablets. As he comes back into the camp, he discovered that in his absence the people had turned from God and was worshiping that which was not God. In his anger, Moses smashed the tablets and commanded the Levites to take up their swords and slay those who were in rebellion and 3000 were killed that day.
If you skip ahead to Acts 2, when the Holy Spirit is poured out on the believers as part of the new convenant, Peter stands up and preaches the message of the great gospel of Christ. After Peter spoke, the book of Acts tells us that 3000 people were saved that day.
The law which brings death has been fully canceled by Spirit, which brings life.