During the 1880 October Session of the General Conference of the Church of Jesus Christ of Latter-day Saints, in connection with revelations added to the Doctrine and Covenants, the Pearl of Great Price was sustained by the conference as "revelations from God," and was implicitly sustained as one of the standard or canonical works recognized by the Church as scripture. The following excerpt relating to this sustaining is extracted from page four of the October 11, 1880 issue of the Salt Lake Tribune. A full copy of this page of the paper can be seen here.
As the image of the newspaper is in relatively poor condition, the content of the paper is provided below:
George Q. Cannon said I hold in my hand the Book of Doctrine and Covenants and also the book The Pearl of Great Price, which books contain revelations of God. In Kirtland, the Doctrine and Covenants in its original form, as first printed, was submitted to the officers of the Church and the members of the Church to vote upon[.] As there have been additions made to it by the publishing of revelations which were not contained in the original edition, it has been deemed wise to submit these books with their contents to the Conference, to see whether the Conference will vote to accept the books and their contents as from God, and binding upon us as a people and as a Church.
Joseph F. Smith said I move that we receive and accept the revelations contained in these books as revelations from God to the Church of Jesus Christ of Latter-day Saints, and to all the world[.]
The motion was seconded and sustained by unanimous vote of the whole Conference.