Joseph Smith, Sr., with his father Asael, older brother Jesse, and thirteen others, signed a declaration of membership in the Tunbridge Universalist society. The major tenet, according to their convention in New Hampshire in 1803, was belief in "one God, whose nature is love, revealed in one Lord Jesus Christ, by one Holy Spirit of Grace, who will finally restore the whole family of mankind to holiness and happiness". The signers, in compliance with Vermont law, declared exemption from "any tax towards the support of any teacher of any different denomination whatever," meaning the usual town tax for support of the Congregational church. This is the only known document that identifies Joseph Smith, Sr., with the Universalists.
[Source: Tunbridge Town Record, 6 December 1797, Book A, 188, Tunbridge Town Clerk's Office, Tunbridge, Vermont., as cited in Dan Vogel, Early Mormon Documents: Tunbridge (Vt) Universalist Society]