Of all the religious figures Franklin meets, Hemphill's one of the few that gets him into church. Hemphill is, Franklin thinks, a great preacher who really concentrates on virtue. So many other preachers talk about being virtuous in a purely religious sense, like only looking inward instead of expanding virtue out into all aspects of your life, and Hemphill's one of the few guys who talks about this larger sense of virtue. Franklin helps him write some promotional material – that's how much he likes him.
Unfortunately, Hemphill gets kicked out of the pulpit when it's discovered that he doesn't write all his own sermons from scratch – he incorporates uncredited material from other sermons. This is seen by most of his congregants as an early case of plagiarism. Franklin doesn't mind, though, because he prefers quality to originality, but he finds himself in the minority on this one. Kind of a strange attitude, right? Franklin would probably be in the minority today too – as you may know, today we really prioritize originality when it comes to ideas. This reminds us of how Franklin doesn't place as much value on getting credit for things as he does on making them happen – a good outcome's more important to him than who made it happen. After Hemphill's departure from the church, Franklin doesn't return either.