Isaac Backus (1724 – 1806) was a Baptist preacher and a delegate to the First Continental Congress.
Born in the village of Yantic, near the town of Norwich, Connecticut, Backus was influenced by the Great Awakening and the works of Jonathan Edwards and George Whitefield. For five years, he was a member of a Separatist Congregationalist church. In 1746, he became a preacher. He was ordained in 1748. Backus became a Baptist in 1751 when he became pastor of the Middleborough Baptist Church in Middleborough, Massachusetts. In 1774 Backus served as a delegate from Middleborough to the Massachusetts convention. The convention ratified the United States Constitution in 1788.
Considered a leading orator of the "pulpit of the American Revolution," Backus published a sermon in 1773 that articulated his desire for religious liberty and a separation of church and state. Called An Appeal to the Public for Religious Liberty, Against the Oppressions of the Present Day, in it Backus stated: "Now who can hear Christ declare, that his kingdom is, not of this world, and yet believe that this blending of church and state together can be pleasing to him?"
Backus also helped found the United States' first Baptist school of higher learning, Rhode Island College (subsequently Brown University).
- Allison, William Henry. "Isaac Backus." Dictionary of American Biography. Vol I., p. 471. New York: Charles Scribner's Sons, 1928, 1943.
- Backus, Isaac. A History of New England with Particular Reference to the Denomination of Christians Called Baptists. 2nd ed, with notes by David Weston. 2 vols. Newton, MA: Backus Historical Society, 1871.
- The Diary of Isaac Backus. William G. McLoughlin, ed. 3 vol. Providence: Brown University Press, 1979.
- Grenz, Stanley J. "Church and State: The Legacy of Isaac Backus." Center Journal 2 (Spring 1983): 73-94.
- "Isaac Backus: Eighteenth Century Light on the Contemporary School Prayer Issue." Perspectives in Religious Studies 13 (Winter, 1986): 35-45.
- "Isaac Backus and Religious Liberty." Foundations 22 (October/December 1979): 352-360.
- Isaac Backus, Puritan and Baptist: His Place in History, His Thought, and Their Implications for Modern Baptist Theology. Macon, GA: Mercer University Press, 1983.
- Hovey, Alvah. A Memoir of the Life and Times of the Rev. Isaac Backus, A.M. Boston: Gould and Lincoln, 1859.
- Little, David. "American Civil Religion and the Rise of Pluralism." Union Seminary Quarterly Review 38 (3-4, 1984): 401-413.
- Maston, T.B. Isaac Backus: Pioneer of Religious Liberty. London: James Clarke & Co. Ltd., 1962.
- McLoughlin, William G. "Isaac Backus and the Separation of Church and State in America." American Historical Review 73 (June, 1968): 1392-1413.
- The Papers of Isaac Backus, 1630-1806. Leigh Johnsen, ed. 15 microfilm reels. Ann Arbor, Mich.: ProQuest Information and Learning, 2003.
- Isaac Backus on Church, State, and Calvinism: Pamphlets, 1754-1789. Cambridge, Mass.: Harvard University Press, 1968.
- Isaac Backus and the American Pietistic Tradition. (Boston: Little, Brown and Company, 1967.