David was an ancient Middle Eastern king. In his youth, he slew Goliath, despite the latter's enormous stature and superior weapons. An account of his life was in the Bible.
The artist Michelangelo was famous for his sculpture of David. (TNG: "Birthright, Part I")
In 2376, The Doctor on the USS Voyager determined that a pathogen had killed all the adult Borg drones on a cube in the Delta Quadrant. In showing the pathogen to Captain Kathryn Janeway and Tuvok, The Doctor remarked, "Behold! The David that slew our Goliath." (VOY: "Collective")
In the Hebrew Bible, David is the father of Solomon.