It outlined the history of the Latter Day Saint movement up to that time, and included Mormonism's Articles of Faith.
The letter was written in response to Wentworth's inquiry on behalf of one of his friends, George Barstow, who was writing a history of New Hampshire.
A similar letter (with some slight revisions) was published by Daniel Rupp in 1844 in a book called An Original History of the Religious Denominations at Present Existing in the United States.
the Standard of Truth has been erected; no unhallowed hand can stop the work from progressing; persecutions may rage, mobs may combine, armies may assemble, calumny may defame, but the truth of God will go forth boldly, nobly, and independent, till it has penetrated every continent, visited every clime, swept every country, and sounded in every ear, till the purposes of God shall be accomplished, and the Great Jehovah shall say the work is done.” (History of the Church 4:540) Fourth, it ends with the statements which later became the Articles of Faith.
B. H. Roberts said of these, “These Articles of Faith were not produced by the labored efforts and harmonized contentions of scholastics, but were struck off by one inspired mind at a single effort to make a declaration of that which is most assuredly believed by the church, for one making earnest inquiry about the truth."
"The combined directness, perspicuity, simplicity and comprehensiveness of this statement of the principles of our religion may be relied upon as strong evidence of a divine inspiration resting upon the Prophet, Joseph Smith.” (B. H. Roberts, Comprehensive History of the Church, Vol.2, Ch.47, p.131) And finally, the Wentworth letter re-establishes Joseph Smith's teachings that the Lamanites are the principal ancestors of the American Indians.
The eleventh article originally read, "We claim the privilege of worshiping Almighty God according to the dictates of our conscience,..." Joseph Fielding Smith wrote: “The reason for the adding of the word "principles," and that is the only change, was because the brethren considered when they were preparing the 1921 edition for publication of the D&C, that the term ordinances did not fully cover the article completely.