What role does religion play in the film?

I can speak for the book. Though it is not at the forefront of Northup's narrative, religion plays a crucial role in his story. Northup uses religion to emphasize which characters are "good" and which are "bad." For example, Tibeats and Epp both swear profusely and use God's name in vain, emphasizing their poor character. By contrast, Ford never takes God's name in vain and is depicted as a devout worshiper of God. Ford even holds sermons and invites his slaves to participate in sharing the word of God. In 1853, when this book was published, these characteristics would have stood out to readers. Furthermore, Northup portrays himself as a religious person on multiple occasions, such as when, after successfully fleeing through a snake-infested forest, Northup credits God for his survival. Religion was comforting to slaves held in bondage, offering them visions of an afterlife in which they could be free from suffering and connect with those they'd lost on earth.