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Pergunta: Quais são as Palestras sobre Fé?
Question: What are the Lectures on Faith?
The Lectures were published in 1835 as the Doctrine portion of The Doctrine and Covenants of the Church of the Latter Day Saints
The Lectures on Faith are seven lessons on theology delivered by the presiding officers of the Church to the School of the Elders at Kirtland, Ohio, in late 1834. The lectures are organized in the form of a catechism, with each lecture starting with instructions on doctrine, and the first five lectures concluding with a question-and-answer section to check class participants for understanding. Scholarship seems to indicate that the lectures were mostly written by Sidney Rigdon with some oversight of Joseph Smith. 
The Lectures were the "doctrine" portion of the Doctrine and Covenants
The Lectures were included as the "doctrine" portion of the 1835 Doctrine and Covenants (the revelations comprised the "covenants" portion). The Lectures were suggested to be added to this version of the D&C by a committee appointed on September 24, 1834 by a general assembly of the church to arrange the doctrines and revelations of the church into a single volume. That committee consisted of Joseph Smith, Oliver Cowdery, Sidney Rigdon, and Frederick G. Williams. The general body of the church accepted the committee's compilation on August 17, 1835 as "the doctrine and covenants of their faith, by a unanimous vote." 
While the Lectures on Faith were at one time included in the Doctrine and Covenants, they were subsequently removed from the 1921 edition (along with other items; for more information see D&C Textual Changes) that were not considered official revelation and binding doctrine by the church.
- See Larry E. Dahl, "Lectures on Faith," in Encyclopedia of Mormonism, 4 vols., edited by Daniel H. Ludlow, (New York, Macmillan Publishing, 1992), 2:818–821. off-site off-site
- Joseph Smith, History of The Church of Jesus Christ of Latter-day Saints, 7 volumes, edited by Brigham H. Roberts, (Salt Lake City: Deseret Book, 1957), 2:243–246. BYU Studies link