Joseph Fielding Smith, Doctrines of Salvation Vol. 1, p.4

“The Father and the Son appeared to the Prophet Joseph Smith before the Church was organized and the priesthood restored to the earth. Under those conditions the Lord could appear to one who sought for light as he did in the case of Joseph Smith.

“Now that the Church is organized, and the power of the priesthood is here, no one can see the face of God, even the Father, without the blessings of the gospel and the authority of the priesthood.”