"A City upon a Hill" is a phrase from the parable of Salt and Light in Jesus's Sermon on the Mount. In Matthew 5:14, he tells his listeners, "You are the light of the world. A city that is set on a hill cannot be hidden." It has become popular with American politicians.
The phrase entered the American lexicon early in its colonial history through the 1630 sermon "A Model of Christian Charity" preached by Puritan John Winthrop while still aboard the ship Arbella. Winthrop admonished the future Massachusetts Bay colonists that their new community would be "as a city upon a hill", watched by the world—which became the ideal that the New England colonists placed upon their hilly capital city of Boston. The Puritans' community in New England would set an example of communal charity, affection, and unity to the world or, if the Puritans failed to uphold their covenant of God, "we shall be made a story and a by-word through the world" of God's judgment. Winthrop's sermon gave rise to the widespread belief that the United States of America is "God's country" because, metaphorically, it is a "Shining City upon a Hill," an early example of American exceptionalism.
In the twentieth century, the image was used a number of times in American politics. On 9 January 1961, President-Elect John F. Kennedy returned the phrase to prominence during delivered to the General Court of Massachusetts:
... I have been guided by the standard John Winthrop set before his shipmates on the flagship Arbella three hundred and thirty-one years ago, as they, too, faced the task of building a new government on a perilous frontier. "We must always consider", he said, "that we shall be as a city upon a hill—the eyes of all people are upon us". Today the eyes of all people are truly upon us—and our governments, in every branch, at every level, national, state and local, must be as a city upon a hill—constructed and inhabited by men aware of their great trust and their great responsibilities. For we are setting out upon a voyage in 1961 no less hazardous than that undertaken by the Arbella in 1630. We are committing ourselves to tasks of statecraft no less awesome than that of governing the Massachusetts Bay Colony, beset as it was then by terror without and disorder within. History will not judge our endeavors—and a government cannot be selected—merely on the basis of color or creed or even party affiliation. Neither will competence and loyalty and stature, while essential to the utmost, suffice in times such as these. For of those to whom much is given, much is required ...