As a means of memetic conservation, religions are amazing.
The Catholics still release all of their official documents in Latin, a language that disappeared in its natural habitat about 1,500 years ago (and conducted all of their rituals around the world in Latin until 1964).
Many Protestants, while not quite as archaic, prefer the now fancy sounding language of the King James Bible, with its “Thou”s and “art”s. (And many other Christian denominations preserve other archaic languages, like Koine Greek in the Greek Orthodox Church, Coptic in Coptic churches and Church Slavonic in, I guess, Slavic churches, and German among the Amish.)
Islam preserves the 7th century Arabic of the Qu’ran (apparently “written” Arabic and “spoken” Arabic are quite distinct, somewhat like if everyone in Italy spoke “Italian” but wrote in 7th century church Latin.)
Diasporic Judaism preserved Hebrew for almost 2,000 years after the destruction of the Temple, and managed to do a good enough job that it has been revived and is now the official language of Israel. (I think Arabic is, too.)
Sanskrit plays the same role for Hinduism, Jainism, and some Buddhist sects. The oldest known work in Sanskrit, the Rigveda, was composed a bit over 3,000 years ago, though I do not know if modern Sanskrit speakers find the Rigveda any more intelligible than I find Beowulf. [note: see the comments for a better explanation of the origins of the Rigveda.]
According to the Wikipedia,
Theravada Buddhism uses Pali as its main liturgical language, and prefers its scriptures to be studied in the original Pali. In Thailand, Pali is written using the Thai alphabet, resulting in a Thai pronunciation of the Pali language.
… In some Japanese rituals, Chinese texts are read out or recited with the Japanese pronunciations of their constituent characters, resulting in something unintelligible in both languages.
(Apparently the Tamil language is also important in Hinduism.)
If you want to preserve a language, write some religious texts in it and then insist that everyone has to learn your language in order to participate in your worship services and go to Heaven.
On top of this, the Christian Bible preserves the Jewish scriptures that predate it. You’re probably so used to this that you don’t even really notice it, but it’s actually pretty weird. So you’re going along in your Christian Bible study, learning about Jesus and whatnot, and then there are these obscure bits of Judean political history from 1,000 BC or something. Like that time King Ahab wanted to buy a field but the farmer wouldn’t sell it to him, so the queen had the farmer executed and then he took it. Or that time in Judges when Ehud assassinated King Eglon.
The Bible also preserves the Jewish Law, which, of course, Christians don’t actually follow. EG:
When men fight with one another, and the wife of the one draws near to rescue her husband from the hand of him who is beating him, and puts out her hand and seizes him by the private parts, then you shall cut off her hand. Deuteronomy 25:11-12
Okay, so if your wife tried to physically drag you out of a fight by your testicles you would probably be in horrible pain as a result, but it doesn’t seem like the sort of situation that comes up very often. But remember, the law also bans pork. I can understand why the Jews think it’s important that their religious book still have all of the notes about not eating bacon or boiling goats in milk or wearing mixed fibers, because The Law is still really important to them. But why on Earth do Christians?
Then take a festival like Purim. Purim is kind of like the Jewish Halloween, but with more Bible and no devils. Kids dress up in costumes, eat a bunch of sweets, go to synagogue, listen to the story of Queen Esther, and everyone makes a bunch of noise to “blot out the name” of some Persian court official who tried to massacre the Jews about 2,500 years ago.
Of course, if there weren’t a holiday devoted to the subject, no one would remember the guy’s name at all; at this point, we’re not even sure if the story is true.
The fact that Judaism is considered a “major world religion” at all is because a chunk of it is inside Christianity; there actually aren’t that many Jews. More people practice some form of Voodoo/Vodun than Judaism, but when’s the last time you saw Voodoo listed as a major world religion?
I got laughed at in school for listing Voodoo as one of the 5 major world religions.
The Christmas rituals (gifts, tree,) also date back thousands of years to ancient Roman and German pre-Christian practices.
And, of course, there’s morality. Obviously many liberal branches of religion toss out moral precepts and adopt new ones as they see fit, but the presence of a line in the text explicitly banning (or encouraging) something seems to have a long-term effect. (Take snake-handling Christian sects, which take the line in the Bible about Christians being able to drink poison and handle snakes without getting killed very seriously.)
Personally, I think the Gospels have a very socialist feel to them. Of course, I am applying a completely anachronistic political label to something that predates “socialism” by nearly two millennia, but I think you know what I mean. All of that business about “give away allof your earthly goods to the poor and come follow me,” or “it is easier for a rich man to fit through the eye of a needle than to enter Heaven,” or the disciples holding all of their property in common in the Book of Acts.
As a result, Christianity has created many charitable or even socialist movements over the past two thousand years, and will probably keep doing so. The “Christian Communists” of the 1800s, like the Shakers, are one set of examples.
Secular “religions” can be memetically conservative, too. Take the American “Thanksgiving”–every year, people get together with their families to eat turkey (the ritual feast) and watch football because approximately 400 years ago, some Pilgrims had a good harvest and so didn’t all die in the winter. Most of us probably aren’t even related to the Pilgrims, but we do it anyway.
Conservatives, as I’ve noted, treat the Constitution kind of like a religious founding document.
Much of the time, the explicit justification for religious rituals has little to do with why people actually observe them. Most Americans don’t really care about the Pilgrims one way or another; I bet most Jews don’t care about Haman anymore, either. Most Catholics probably think it’d be fine if the church just started publishing official documents in Italian, and even atheists give each other gifts on Christmas. The function of these rituals is often very different from their form–Thanksgiving is really about family togetherness, not Pilgrims. Likewise, the current push to get rid of Columbus day and replace it with Indigenous Culture Day isn’t really a statement that indigenous peoples were better than Columbus (after all, the Aztecs were cannibals.)
The functions of religion are myriad, but marking important life transitions, assuaging fears of death, teaching morality, and binding the community together are all obviously significant. Perhaps religion functions better when the memes are older than when they are newer. Perhaps it doesn’t really matter whether or not you can understand the liturgy, but a liturgy that gives you the impression of being connected to your ancient ancestors may function better than one that doesn’t; a generic “Thanksgiving is a time to be with our families,” may not work as well as a “Thanksgiving is a celebration of the feast between the Pilgrims and the Indians.”
Do you have any other good examples of this phenomenon?