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Pergunta: Será que os líderes da Igreja sempre ensinar que os negros eram neutros na "guerra no céu?"
Question: Did Church leaders ever teach that Blacks were neutral in the "war in heaven?"
Yes, some Church leaders promoted the idea as a way to explain the priesthood ban
Despite the explicit denial of this concept by Brigham Young, the idea that people born with black skin as a result of their behavior in the pre-existence was used by several 20th century Church leaders in order to try and provide an explanation for the priesthood ban.
The First Presidency, in a statement issued on August 17, 1949, actually attributed the ban to "conduct of spirits in the premortal existence"
The First Presidency stated in 1949:
The position of the Church regarding the Negro may be understood when another doctrine of the Church is kept in mind, namely, that the conduct of spirits in the premortal existence has some determining effect upon the conditions and circumstances under which these spirits take on mortality. 
Joseph Fielding Smith said in 1954 that there were no "neutrals in the war in heaven," but that rewards in this life may have "reflected actions taken in the pre-existence
In the 1954 book Doctrines of Salvation (compiled by Bruce R. McConkie), Joseph Fielding Smith stated that "there were no neutrals in the war in heaven," but suggested that the rewards received in this life reflected actions taken in the pre-existence:
NO NEUTRALS IN HEAVEN. There were no neutrals in the war in heaven. All took sides either with Christ or with Satan. Every man had his agency there, and men receive rewards here based upon their actions there, just as they will receive rewards hereafter for deeds done in the body. The Negro, evidently, is receiving the reward he merits. 
Bruce R. McConkie said in 1966 that they were "less valiant" in the pre-existence
The most well known of these was the statement made by Bruce R. McConkie in his book Mormon Doctrine. McConkie offered the following opinion:
Those who were less valiant in the pre-existence and who thereby had certain spiritual restrictions imposed upon them during mortality are known to us as the negroes. Such spirits are sent to earth through the lineage of Cain, the mark put upon him for his rebellion against God and his murder of Abel being a black skin...but this inequality is not of man’s origin. It is the Lord’s doing, based on His eternal laws of justice, and grows out of the lack of spiritual valiance of those concerned in their first estate. 
These statements by Church leaders reflected ideas which were prevalent in society during the 1950s and 1960s
These statements by 20th century leaders did not represent thinking that was unique to the Church, but instead reflected ideas which were much more prevalent in society during the 1950's and 1960's.
When the priesthood ban was lifted in 1978, McConkie retracted what he had said previously
Elder McConkie retracted his previous statements regarding the priesthood ban when it was lifted in 1978:
Forget everything I have said, or what...Brigham Young...or whomsoever has said...that is contrary to the present revelation. We spoke with a limited understanding and without the light and knowledge that now has come into the world. 
- First Presidency Statement (George Albert Smith), August 17, 1949. off-site
- Joseph Fielding Smith, Doctrines of Salvation (Salt Lake City: Bookcraft, 1954) , 1:65-66. (emphasis in original)
- Bruce R. McConkie, Mormon Doctrine (1966), p. 527.
- Bruce R. McConkie, "New Revelation on Priesthood," Priesthood (Salt Lake City: Deseret Book, 1981), 126-137.