For a long time, a sitcom about religion was a hard sell, even harder for viewers, especially in Midwestern & Southern states, where the Bible is taken very seriously, almost to the point of fanatic obsession.
In the mid-70's, the networks tried to make a go of it, as there were two short-lived religious-themed sitcoms. On CBS, you had McLean Stevenson, who had left M*A*S*H, top-lining In The Beginning. I think that was gone well before Christmas.
In the spring of 1976, ABC trotted out Good Heavens, which gave Carl Reiner his first headline role. It was unique in that this was the first half-hour anthology sitcom, and viewers were already accustomed to religious anthologies of a more dramatic bent (i.e. Insight). Mr. Angel (Reiner) granted random, ordinary folks wishes, and if that sounds remotely familiar, well, ABC went back to that particular well, but with a more dramatic, supernatural bent, not too long after Heavens went off the air with the original Fantasy Island. Of course, it might've helped that Columbia Pictures Television (now Sony Pictures Television) actually collaborated with Aaron Spelling on Fantasy Island, since Heavens was one of their bazillion failed properties.
Nearly a decade later, the idea of an angel on earth was revisited, again with a dramatic touch, but this time, over at NBC, when Michael Landon replaced Little House on the Prairie with Highway to Heaven, which lasted a few years. And, then, there was Touched by an Angel, over at CBS. Enough said.
Gilmore Box serves up the intro to Good Heavens:
Bear in mind, of course, that CPT had also sold ABC a delayed follow-up to Bewitched, but misfired by having Tabitha experience a major growth spurt to adulthood, by-passing her teenage years. Small wonder, then that Tabitha lasted a full season and no more. It looked like the days of the fantasy sitcom were coming to an end....!