Justification is a big word that explains something that is at the heart of the Christian faith.  It is the fact that from the time we are born again God treats us 'just as if we had never sinned'.  The reason for this is because Jesus has paid the price for our guilt on the cross.  With the punishment paid it would be unjust if he then punished us again.  So the apostle Paul assures us that there is now no condemnation for those who are in Christ Jesus (Romans 8:1).  He also wrote to the Romans explaining that God is both the one who is just and who justifies 'and the one who justifies those who have faith in Jesus' (Romans 3:26).  A glorious exchange has taken place.  God has taken our sin and placed it on the cross of Christ and he has taken Jesus' perfect obedience and given it to us.  Listen to the following clip from Matt Chandler and let your heart rejoice.