One of the biggest lies the enemy tries to crush us with is that we must change ourselves before Christ will accept us. In Rom. 5: 8, it says that "While we were still sinners, Christ died for us." He didn't wait until we were good enough, changed our lifestyle, quit smoking or whatever a person thinks is a fault too big for Christ's sacrifice to cover.
There is absolutely no way for us to earn salvation. That is the whole point of the cross. We could never be good enough. The most saintly person the earth ever has or will see is not good enough. It is not humanly possible for us to meet God's standards of goodness. This is why it was necessary for Christ to step in and pay the price for us. We need do nothing but accept the gift.
When you receive a present from someone, you don't refuse to accept it until you feel you have earned the right to it. Why would it then not make sense to have the same attitude to Christ's gift to us?
Salvation is the greatest gift from the greatest giver!