Christianity was a Human religion based upon the teachings of Jesus Christ (Jesus of Nazareth), born from the Virgin Mary. The prophets of the Old Testament and New Testament of the Bible like Methuselah, Solomon, Lazarus, and Saint Paul and many saints like Saint Andrew, Saint Émilion, and Saint Moritz also inspired the teaching of the Christian religion.
Christianity was a monotheistic religion, stating that there was one God who created the universe. This one God, however, was both a unity and a trinity in the view of most Christians. There were three persons, God the Father, God the Son and God the Holy Spirit, who although distinct in personhood shared one and the same Godhood. Most images of the Christian God depicted a wise old man, seen as the universal father figure (indeed, God was often called "God the Father"), or Jesus Christ, who is God the Son incarnate as man, or the Holy Spirit with the image of a dove or as fire. In 2287, the entity of Sha Ka Ree assumed this form of the Christian God so as to "better suit the expectations" of the USS Enterprise team who had encountered it. (Star Trek V: The Final Frontier)
The Virgin Mary and Saint Anne were depicted in the Leonardo da Vinci painting The Virgin and Child with St. Anne, which was found among the relics in Kathryn Janeway's da Vinci holodeck program. (VOY: "Scorpion", "The Raven", "Scientific Method", "Concerning Flight")
Christianity was one of the major religions on Earth and was the origin of several well-known beliefs such as the concept of Heaven, Hell, angels, and the Devil. (TOS: "The Cage", "Who Mourns for Adonais?", "Bread and Circuses", "Day of the Dove") Christianity was a major religion in the 21st century and its influences were still felt into the 23rd and 24th centuries – most notably the use of Christian elements in weddings and holiday celebrations like Christmas. (TOS: "Dagger of the Mind", "Balance of Terror"; Star Trek Generations; DS9: "Penumbra")
In predominant Christian beliefs, Hell was the underworld where the dead went, to suffer eternally alongside (not under the rule of) the Devil and his demons. It was believed that people would be sent here after their death if they did not accept Jesus as their savior and as a substitutionary sacrifice to atone for sins against God. During his captivity on Talos IV, Captain Christopher Pike was subjected to an illusion of Hell when he refused to cooperate with his Talosian jailers. (TOS: "The Cage")
The main written work used by Christians was the Bible. The name of the Genesis Device was taken from the Christian Bible (the Book of Genesis) which described the beginnings of life on Earth. (Star Trek II: The Wrath of Khan) A well-known precept from the Bible was "Love your neighbor." (VOY: "Fair Haven")
Parts of the Bible described the end of the world; however, Jean-Luc Picard seemed to indicate a strong distaste for apocalyptic traditions, first when discussing his personal beliefs about the afterlife, (TNG: "Where Silence Has Lease") and again when he was briefly taken by the Mintakans to be their ancient god. (TNG: "Who Watches The Watchers")
In a vision sent to Benjamin Sisko by the Prophets, his father Joseph Sisko took the role of a 1950s preacher. Although Benjamin had never previously heard his father quote from the Bible, after he told his father about his experience the elder Sisko recited, "I have fought the good fight. I have finished the course. I have kept the faith." (DS9: "Far Beyond the Stars")
In 2370, Beverly Crusher attended her grandmother Felisa Howard's funeral on Caldos. The colony leader, Maturin, performed traditional burial rites and used the expression "ashes to ashes and dust to dust." (TNG: "Sub Rosa")
Flint possessed a Gutenberg Bible, a version of the Bible mass-produced during the 15th century, among his collection of extremely rare books. (TOS: "Requiem for Methuselah") Berlinghoff Rasmussen compared being close to Data to examining a rare Gutenberg Bible. (TNG: "A Matter of Time")
Samuel T. Cogley had a Bible in his library in 2267. (TOS: "Court Martial") A copy of the Holy Bible was among the small collection of books found aboard the SS Botany Bay. (Star Trek II: The Wrath of Khan)
The ideas from the Bible were used in many sayings and written literature. Joseph Sisko often told Benjamin that "the road to Hell is paved with good intentions." (DS9: "In the Pale Moonlight") In the 17th century, John Milton of Earth wrote in his poem Paradise Lost that "It is better to rule in Hell than serve in heaven." (TOS: "Space Seed")
An angel was a figure from Christian mythology described as a messenger of God. In a holographic simulation Lord Byron said to Gandhi that "It is said the angels themselves take pleasure in their bodies of light." (VOY: "Darkling") In 2267, Dr. McCoy, expressing frustration at the restrictions of the Prime Directive, joked that he would like to beam down to a primitive planet and say, "Behold, I am the Archangel Gabriel!" (TOS: "Bread and Circuses") In 2375, Jack claimed that his laws-of-physics-bending machine "could clip the wings of an angel dancing on the head of a pin." (DS9: "Chrysalis")
Holy places and rituals
Christians practiced their religion in churches and chapels. In the 2150s, Dr. Phlox of Enterprise NX-01 recalled attending a Mass at Saint Peter's Square in Rome. (ENT: "Cold Front") A 24th century hologram of the Renaissance figure Leonardo da Vinci asked Kathryn Janeway if she would like to pray with him in Santa Croce church. (VOY: "Scorpion")
During a trip back to the year 1930, James T. Kirk explained Spock's unusual ear shape as being caused by an American missionary living in China who was also a plastic surgeon. (TOS: "The City on the Edge of Forever")
Christians sang and played music. Despite Montgomery Scott's disbelief in gods, he played a Christian hymn traditionally associated with Scottish funerals, "Amazing Grace", on the bagpipes at Spock's funeral in 2285. (TOS: "Who Mourns for Adonais?"; Star Trek II: The Wrath of Khan)
In 2376, The Doctor portrayed a Catholic priest in Tom Paris's Fair Haven holoprogram, a simulation of a 19th century Irish village. (VOY: "Fair Haven") During an appearance to the crew of the USS Enterprise-D, Q pretended he was a monk. (TNG: "Hide and Q")
A number of holidays originated in the Christian religion; one called Christmas was experienced by Captain Jean-Luc Picard during his interrogation by Gul Madred, and during his time spent in the Nexus, his visions included one of a traditional Christmas tree. (TNG: "Chain of Command, Part II"; Star Trek Generations) Before that, Christmas parties were celebrated on the USS Enterprise, (TOS: "Dagger of the Mind") and another called Carnival, a traditional celebration before the beginning of the Catholic season of Lent, still celebrated during the 24th century. (DS9: "The Ship")
Children of the Son
In a remarkable example of Hodgkin's Law of Parallel Planetary Development, a cult very similar to early Christianity emerged on the planet 892-IV, called the Children of the Son. They focused on the teachings of the Son, which was analogous to Christ. They opposed the dominant Roman Empire. (TOS: "Bread and Circuses")
There are a number of different types of Christianity. The Christian elements in "Fair Haven" can specifically be recognized as Catholicism (consistent with Ireland in this age), while Presbyterianism was implied in the name of the East Fork Presbyterian Church, in "New Eden".
In "Nor the Battle to the Strong", a wounded soldier (Burke) on Ajilon Prime asked Jake Sisko that he made sure that he died with his eyes directed toward the sky. This was a Christian custom in medieval times, since the sky was believed to be the place where Heaven was located. There are other Christian elements in the episode. The soldier speaks of redemption and the episode title was taken from Ecclesiastes, Chapter 9, Verse 11.
In the Star Trek: Vanguard novel Harbinger, the series' titular station has a non-denominational Christian chapel presided over by Father McKee (β), while the Pocket TNG novel Guises of the Mind portrays Catholicism as still being practiced by the 24th century.