President [Joseph F.] Smith: ... this body of men, this Council of Presidency and Apostles, compose the living constitution of the Church, with power to legislate, judge and decide.
... We represent the government of the holy priesthood, and besides, we are the special witnesses of Jesus Christ, also of Joseph Smith, and of the divinity of this great Latter-day work. ["Instructions given to Elder Joseph F[ielding]. Smith Jr., at the Salt Lake Temple, April 7th, 1910, immediately prior to his receiving ordination as an Apostle," LDS Archives. Note that the "living constitution" previously referred to the now defunct Council of Fifty.]
[First Presidency and Quorum of the Twelve minutes]