It was revealation, at least according to the LDS first presidency…
"Our living prophet, President David O. McKay, has said, "The seeming discrimination by the Church toward the Negro is not something which originated with man; but goes back into the beginning with God…
“Revelation assures us that this plan antedates man’s mortal existence, extending back to man’s pre-existent state.”
President McKay has also said, “Sometime in God’s eternal plan, the Negro will be given the right to hold the priesthood.”
Until God reveals His will in this matter, to him whom we sustain as a prophet, we are bound by that same will. Priesthood, when it is conferred on any man comes as a blessing from God, not of men."
Ouch!