Wilford Woodruff records Brigham's description of the "fullness of the Melchisedec Priesthood."
Citation from Wilford Woodruff's Journal (August 6, 1843) in "History, 1838–1856, volume E-1 [1 July 1843–30 April 1844]," p. 1688, The Joseph Smith Papers website, accessed September 8, 2021
He also remarked that if any in the church had the <fullness of the> Melchisedec Priesthood he did not know it; for any person to have the fulness of that priesthood <he> must be a king and a Priest. A person may have a portion of that Priesthood the same as Governors or Judges of England have power from the king to transact business; but that does not make them kings of England. A person may be anointed king and priest <long> before he receives his kingdom.