There's plenty of religion on Star Trek.
Episodes:
"Fair Haven"
"Nor the Battle to the Strong"
"New Eden"
"Chain of Command, Part II"
"Hide and Q"
"The City on the Edge of Forever"
"Who Mourns for Adonais?"
"Balance of Terror"
"Chrysalis"
"Bread and Circuses"
"Darkling"
"Space Seed"
"In the Pale Moonlight"
"Court Martial"
"A Matter of Time"
"Requiem for Methuselah"
"Sub Rosa"
I'm sure there are more - but I'm tired of researching this.