In a letter dated July 2, 1756, Benjamin Franklin presented a proposal to George Whitefield, the most famous preacher of the Great Awakening, that they partner together to establish a Christian colony "in the Ohio," which was frontier at the time. In the letter, Franklin expressed confidence that God would give them success in such a project, "If we undertook it with a sincere regard to his honor." For the next 30 years, they carried on a lively and open correspondence. Whitefield often spoke about faith in Christ and admonished Franklin to make sure he was prepared for the next...