The film deals with the story of a renowned evangelical minister in Tulsa, Carlton Pearson, who stirred up controversy by claiming that there was no hell.
Reports suggest that Jeffrey Wright of 'Quantum of Solace' may play Pearson while Redford, 77, will be seen as Roberts, who was the mentor of Pearson, the Hollywood Reporter said.
Redford's recent hits include 'Captain America: The Winter Soldier' and 'All Is Lost'.
Marcus Hinchey of 'All Good Things' fame has written the screenplay which is based on 'This American Life' broadcast aired in 2005.