(covers information from several alternate timelines)
Jesus Christ was a central figure in the Human religion of Christianity. According to the Bible, he was the son of God (TOS: "Bread and Circuses") born to a virgin named Mary, the saviour of His people. (VOY: "The Killing Game") The teachings of Christ, a philosophy of total love and brotherhood, would become the foundation for the Christian faith.
His words were well known and occasionally quoted, for example by James T. Kirk, Spock, Montgomery Scott, Harry Mudd, Kathryn Janeway, Tom Paris, and The Doctor. (Star Trek II: The Wrath of Khan, TOS: "The Trouble with Tribbles", TOS: "The Empath", TOS: "I, Mudd", VOY: "Good Shepherd", VOY: "Year of Hell", VOY: "Fair Haven")
The imperial Roman planet 892-IV began spreading the word of the "Son" during their 20th century. At that time, the crew of the USS Enterprise visited that planet, where they misconstrued it as "sun" worship. Uhura later discovered that this was not the sun in the sky, but the Son of God, prompting Kirk to muse, "Caesar and Christ. They had them both. And the word is spreading only now." (TOS: "Bread and Circuses")
Jesus' name was prone to be used as a proclamation or an intensifier. For example, upon seeing the USS Enterprise-E during his first warp flight, Zefram Cochrane exclaimed "Sweet Jesus". The same expression was used by Leonard McCoy while attempting to save Klingon Chancellor Gorkon. The phrase "for Christ's sake" was used by Douglas Pabst while stressing to Benny Russell how unbelievable the concept of a Negro captain of a space station in the future was. (Star Trek: First Contact; Star Trek VI: The Undiscovered Country; DS9: "Far Beyond the Stars")