One thing that I’ve discovered in my time with Jesus and in reading His Word, is that Grace is the amazing gift that we receive in order to obtain salvation (and more!). But grace without repentance is dead.
I have often heard preached: “God see’s you as He see’s Jesus.” Yes, Jesus took all our sin on the cross and paid the price, because we could not afford to pay the price for even the smallest of sins. However, the price He paid was for us to be able to walk out of sin – so if there is no change in your life (repentance), then the gift of grace you have received is dead.
To put it another way, God does see us as a beautiful butterfly when we are still a caterpilla. We can say to ourselves “I am a beautiful butterfly now!” – and this is true, but unless we actually GROW into the butterfly, then we are nothing but a deceived caterpilla.
Repentance is not an act of personal perfectionism to make ourselves right before God, but it is the power to change because of what Jesus has done on the cross, and because of what God is doing in us.
For more on this, refer to this article: http://lifebythespirit.org/2009/11/23/when-are-we-actually-saved/