Why will Proctor not let Danforth have his signed paper?

Danforth demands that Proctor sign the document. Proctor says that he has confessed to God, and that is enough. He asks Danforth whether a good penitence must be public. Proctor asks how he can teach his children to walk like men when he has sold his friends. Proctor wishes to keep only his name, and Danforth thus refuses to accept his confession. Danforth orders Proctor to be hanged.