Faith

In A Tale of Two Cities, Charles Darnay refused to believe that Carton could exchange places with him. He was sure that Carton would merely add his name to the list of those to be executed. Consequently, in order to make his planned exchange succeed, Carton had to drug the reluctant Darnay.

Like Carton, Jesus came to exchange places with us. The free and sinless came to exchange places with the imprisoned and condemned. However, unlike Carton, Jesus requires that we put our trust in him. He requires that we believe that he is the one the Father sent to set us free and that he is capable of doing so. Jesus said it this way,

"I told you that you would die in your sins; if you do not believe that I am the one I claim to be, you will indeed die in your sins."
-- John 8:24

If we don't believe, he will not force us to exchange places with him. If we would scoff at his naivety or cower silently in the back of our cell, he does not impose himself on us. He wants us to believe with enough confidence to call upon him, to confess him as savior.

For it is with your heart that you believe and are justified, and it is with your mouth that you confess and are saved.
-- Romans 10:10