[quote]There was the episode which took place on a planet influenced by ancient Rome with some type of rebellion from a sect of people, called the Followers of the Sun or something. At the end of the episode, Uhura says something like "They weren't followers of the sun, but the Son. The Son of God - Jesus Christ".
R67 and R78, that was '𝐁𝐫𝐞𝐚𝐝 𝐚𝐧𝐝 𝐂𝐢𝐫𝐜𝐮𝐬𝐞𝐬' S2E14. The lines ran like this:
KIRK: Gentlemen.
MCCOY: Captain, I see on your report Flavius was killed. I am sorry. I liked that huge sun worshiper.
SPOCK: I wish we could have examined that belief of his more closely. It seems illogical for a sun worshiper to develop a philosophy of total brotherhood. Sun worship is usually a primitive superstition religion.
UHURA: I'm afraid you have it all wrong, Mister Spock, all of you. I've been monitoring some of their old-style radio waves, the empire spokesman trying to ridicule their religion. But he couldn't. Don't you understand? It's not the sun up in the sky. It's the Son of God.
KIRK: Caesar and Christ. They had them both. And the word is spreading only now.
MCCOY: A philosophy of total love and total brotherhood.
SPOCK: It will replace their imperial Rome, but it will happen in their twentieth century.
KIRK: Wouldn't it be something to watch, to be a part of? To see it happen, all over again? Mister Chekov, take us out of orbit. Ahead warp factor one.
CHEKOV: Aye, sir.
I've always detested that episode. "To see it happen, all over again" is particularly nauseating.
There was often a struggle between a given episode writer, Roddenberry, and his superiors at NBC, over religious content. A clash occurred over a line in 𝐖𝐡𝐨 𝐌𝐨𝐮𝐫𝐧𝐬 𝐅𝐨𝐫 𝐀𝐝𝐨𝐧𝐚𝐢𝐬?, where Kirk states, "Mankind has no need for gods"; S&P forced the insertion of a line to clarify, "We find the 𝑂𝑛𝑒 quite adequate."
This site has a list of instances in 'Trek' which have a bearing on religion:
(They don't seem to mention Mr Spock's statement from '𝐓𝐡𝐞 𝐆𝐚𝐥𝐢𝐥𝐞𝐨 𝐒𝐞𝐯𝐞𝐧', "I, for one, do not believe in angels.")