Since the beginning of time or should it be said, since the beginning of man, contrariness to God has been the mindset of the human condition.
Jesus gave His life to make a way for anyone who will, to return to the way God intended. Jesus said that He is the Way, the Truth and the Life. What was impossible to do for ourselves, Jesus did.
We cannot earn, buy, steal, manipulate, beg or borrow our right to heaven. If we could, then Jesus would not have had to give His life in our place. He is the perfect sacrifice, we could never be. Eternity rests on the choice we make in this life to accept that perfect sacrifice.