Heaven, sir, is invitation only and repentance a daily occurence for any Christian who is half way honest with himself about himself. God has to act inorder for someone to not got to hell. Hell is mankind's natural end. It took and still takes devine intervention to prevent it.
That is after all the whole point of the scripture were. It is by grace you are saved, through faith and that not of yourself it is the gift of God,... I am saved, if indeed I am, solely because God chose, for his own reasons, to write my name in the Book of Life ere he ever said let their be light.