Question: “Will you please tell us which of the ancient prophets came and restored the keys of missionary work?”
Answer: The keys or power to go forth and proclaim the gospel was restored to Joseph Smith and Oliver Cowdery when Peter, James, and John conferred upon them the Melchizedek Priesthood before the organization of the Church. It is true that John the Baptist had conferred upon them the keys of the Aaronic Priesthood before the Melchizedek Priesthood was restored. This was necessary because the time had come for them to be baptized and hold this priesthood preparatory to the coming of the higher priesthood.
Joseph Fielding Smith, Answers to Gospel Questions, Vol 1, Chapter 33
The answer by Smith continues explaining when this authority was given, including revelations from “God.” Ending the answer right here is sufficient to destroy this teaching.
First: Peter, James, and John were not prophets; they were apostles.
Second: Neither these apostles nor John the Baptist were priests and so held no priesthood to pass on.
Third: In order to even have a qualification for the “Aaronic” priesthood (actually Levitical), one must be a member of the tribe of Levi, and nothing in Scripture says these men were Levites, and certainly neither Joseph Smith nor Oliver Cowdery were Levites. The O.T. clearly says that only direct descendants of the tribe of Levi can hold the priesthood (Ex. 28:1, Num. 18:1-7, Lev. 6:19-23, Nehemiah 7:61-65). Additionally, to be ordained as a Levitical priest, there were certain rituals required that LDS does not perform (Ex. 29:4-27). The need for a Levitical priest was done away with when the temple veil was rent at Jesus' crucifixion. (Interestingly, D&C 107:16 even states that one must “be a literal descendant of Aaron” to hold this priesthood!)
Fourth: NO ONE can pass on the Melchizedek priesthood, since it was a priesthood of ONE, and that is Jesus Christ. See my article, The Melchizedek Priesthood, for a detailed discussion proving the Mormons do not have this priesthood.
Finally: DEAD people do not return to earth for anything, nor do dead people become angels as Mormons teach.
Since all the above counter Biblical teachings, this also means that Joseph Smith never had a revelation from God because God does not contradict himself!
The Mormons have no priesthood—period.