Mormon Doctrine, pg. 396; “Joseph Smith’s greatness lies in the work that he did, the spiritual capacity he developed, and the witness he bore of the Redeemer. Since the keys of salvation were restored to the Prophet, it is in and through and because of his latter-day mission that the full redemptive power of the Lord has again become available to men. It is because the Lord called Joseph Smith that salvation is again available to mortal men. “Joseph Smith, the Prophet and Seer of the Lord, has done more, save Jesus only, for the salvation of men in this world, than any other man that ever lived in it.” (D. & C. 135:3.)”
John 15:13, 15; “Greater love hath no man than this, that a man lay down his life for his friends. 15 Henceforth I call you not servants; for the servant knoweth not what his lord doeth: but I have called you friends; for all things that I have heard of my Father I have made known unto you.”
If Jesus was going to come back and give the “keys of salvation” to Joseph Smith then WHY DID HE DIE?