President Thomas Jefferson was instrumental in establishing weekly Sunday worship services at the U. S. Capitol (a practice that continued through the 19th century) and was himself a regular and faithful attendant at those church services, not even allowing inclement weather to dissuade his weekly horseback travel to the Capitol church.
Why was Jefferson a faithful attendant at the Sunday church at the Capitol? He once explained to a friend while they were walking to church together: “No nation has ever existed or been governed without religion. Nor can be. The Christian religion is the best religion that has been given to man and I, as Chief Magistrate of this nation, am bound to give it the sanction of my example.” President Jefferson even closed presidential documents with “In the year of our Lord Christ”
Sources: (1) February 18, 1801, available in the Maryland Diocesan Archives; The First Forty Years of Washington Society, Galliard Hunt, editor (New York: Charles Scribner’s Sons, 1906), p. 13; (2) Life, Journal, and Correspondence of Rev. Manasseh Cutler (Cincinnati: Colin Robert Clarke & Co., 1888), Vol. II, p. 119, in a letter to Dr. Joseph Torrey on January 3, 1803; see also his entry of December 26, 1802 (Vol. II, p. 114).