The promise is that our Messiah has been delivered up for us so that we are counted as righteous and we have salvation through Him, meaning Jesus Christ. In no way was the promise Joseph Smith!
Here’s what Isaiah 29:13-14 says in context; “Wherefore the Lord said, Forasmuch as this people draw near me with their mouth, and with their lips do honour me, but have removed their heart far from me, and their fear toward me is taught by the precept of men: 14 Therefore, behold, I will proceed to do a marvellous work among this people, even a marvellous work and a wonder: for the wisdom of their wise men shall perish, and the understanding of their prudent men shall be hid.”
“The Lord has fulfilled His promise. The “choice seer” has come forth. The prophet “like unto Moses” has been raised up. “A marvellous work and a wonder” (Isaiah 29:13-14) has been set in full motion among the children of men “in the latter days.”
Therefore, by the power of the Lord, this new prophet of this dispensation has given us some one hundred and thirty revelations direct from the Lord, which are recorded in the Doctrine and Covenants, a book of some 250 pages. These revelations were given to direct this prophet and his successors in the establishment of the Church and Kingdom of God upon the earth in these latter days to prepare the way for the second coming of the Messiah.” Legrand Richards,Israel! Do You Know? [Salt Lake City: Deseret Book Co., 1954], 123-4.