This is the last of four revelations Joseph Smith received in September 1830 (see D&C 28; 29; 30). At the time, Thomas may have been worried about moving his family from their home in Boston, Massachusetts, to the Fayette, New York, area to be closer to the other members of the Church. In fulfillment of the Lord’s promise, Thomas became a great missionary for the Church and was eventually called to serve as the first President of the Quorum of the Twelve Apostles in this dispensation. Hyrum Smith and Janne M. Sjodahl later noted, “As long as Thomas B. Marsh was faithful he was an eloquent speaker. At the time of the troubles in Clay County, Mo., he was elected member of a committee to lay the grievances of the Saints before the authorities of the State. On that occasion he spoke so impressively that General Atchison [one of the Saints’ worst enemies], who was present, shed tears, and the meeting passed resolutions to assist the Saints in finding a new location” (Doctrine and Covenants Commentary, 1951, 165).

Significantly, Thomas was exhorted to “declare the things which have been revealed to my servant, Joseph Smith, Jun” (D&C 31:4). Another commentator on the Doctrine and Covenants has noted how this commandment also applies to members of the Church today:

This revelation announces how we as a people are to present our message to the world. Though it is common practice among members of the Church to seek common ground with those who profess faith in Christ by an appeal to the Bible, the direction given in this revelation is that we declare the things that have been revealed through the Prophet Joseph Smith. The message of the Restoration centers on the idea that it is not common ground we seek in sharing the gospel. There is nothing common about our message. The way we answer questions about our faith ought to be by finding the quickest and most direct route through the Sacred Grove. That is our ground. It is sacred ground. It is where testimonies are born and the greatest truths of heaven are unveiled.

We claim no priesthood, keys, power, authority, or doctrines that do not trace themselves directly to heaven. We have not built upon the theological rubble of the past. All that we have, and this includes our faith in the Bible and our understanding of it, has come to us by direct revelation in this dispensation. Doctrines from any other source are without authority among the Latter-day Saints. All doctrine and authority must come through the channels the Lord has ordained for our dispensation, and that channel is the priesthood and keys restored to the Prophet Joseph Smith. (Joseph Fielding McConkie and Craig J. Ostler, Revelations of the Restoration, 2000, 247)