Genesis 50

As the Prophet Joseph Smith was concluding his translation of the Bible (JST), he added much more to the prophesies of Joseph to his brethren.  I would assume that this was had at the time of Moses wrote his record for much of this prophecy was had in the plates of Laban (or Book of Mormon).  But whether Joseph Smith received this additional material by revelation, not being had previously or not, it does not matter to me other than I find it inspirational as he adds ( included the bracketed comments by David J Ridges for additional information from whom I retrieved the translation) -

"And Joseph said unto his brethren, I die, and go unto my fathers; and I go down to my grave with joy. The God of father Jacob be with you, to deliver you out of affliction in the days of your bondage; for the Lord hath visited me, and I have obtained a promise of the Lord, that out of the fruit of my loins, the Lord God will raise up a righteous branch out of my loins; and unto thee, whom my father Jacob hath named Israel, a prophet; (not the Messiah who is called Shilo;) and this prophet [Moses] shall deliver my people out of Egypt in the days of thy bondage.
25 And it shall come to pass that they shall be scattered again; and a branch shall be broken off, and shall be carried into a far country; nevertheless they shall be remembered in the covenants of the Lord, when the Messiah cometh; for he shall be made manifest unto them in the latter days, in the Spirit of power; and shall bring them out of darkness into light; out of hidden darkness, and out of captivity unto freedom.
26 A seer shall the Lord my God raise up, who shall be a choice seer unto the fruit of my loins.
27 Thus saith the Lord God of my fathers unto me, A choice seer [Joseph Smith] will I raise up out of the fruit of thy loins, and he shall be esteemed highly among the fruit of thy loins; and unto him will I give commandment that he shall do a work for the fruit of thy loins, his brethren.
28 And he shall bring them to the knowledge of the covenants which I have made with thy fathers [the ancestors of Joseph in Egypt, including Abraham, Isaac, and Jacob]; and he [Joseph Smith] shall do whatsoever work I shall command him.
29 And I will make him [Joseph Smith] great in mine eyes, for he shall do my work; and he shall be great like unto him [Moses] whom I have said I would raise up unto you, to deliver my people, O house of Israel, out of the land of Egypt; for a seer [Moses] will I raise up to deliver my people out of the land of Egypt; and he shall be called Moses. And by this name he shall know that he is of thy house; for he shall be nursed by the king’s daughter, and shall be called her son.
30 And again, a seer [Joseph Smith] will I raise up out of the fruit of thy loins [Joseph Smith will be a descendant of Joseph in Egypt], and unto him will I give power to bring forth my word unto the seed of thy loins; and not to the bringing forth of my word only, saith the Lord, but to the convincing them of my word [the Bible], which shall have already gone forth among them in the last days;
31 Wherefore the fruit of thy loins shall write [the Book of Mormon], and the fruit of the loins of Judah shall write [the Bible]; and that which shall be written by the fruit of thy loins, and also that which shall be written by the fruit of the loins of Judah [the Book of Mormon and the Bible], shall grow together unto the confounding of false doctrines, and laying down of contentions, and establishing peace among the fruit of thy loins, and bringing them to a knowledge of their fathers in the latter days; and also to the knowledge of my covenants, saith the Lord.
32 And out of weakness shall he [Joseph Smith] be made strong, in that day when my work shall go forth among all my people, which shall restore them, who are of the house of Israel, in the last days.
33 And that seer [Joseph Smith Jr.] will I bless, and they that seek to destroy him shall be confounded [those who seek to destroy his work will not succeed]; for this promise I give unto you; for I will remember you from generation to generation; and his name shall be called Joseph [Joseph Smith Jr.], and it shall be after the name of his father [his father will also be named Joseph]; and he shall be like unto you; for the thing which the Lord shall bring forth by his hand shall bring my people unto salvation.
34 And the Lord sware unto [covenanted with] Joseph that he would preserve his seed for ever, saying, I will raise up Moses, and a rod shall be in his hand, and he shall gather together my people, and he shall lead them as a flock, and he shall smite the waters of the Red Sea with his rod.
35 And he shall have judgment, and shall write the word of the Lord [Genesis, Exodus, Leviticus, Numbers, Deuteronomy]. And he shall not speak many words, for I will write unto him my law by the finger of mine own hand [the Ten Commandments tablets]. And I will make a spokesman for him, and his name shall be called Aaron."  (JST - Genesis 50: 24-35)

I wonder if this is had in some old record like the Dead Sea Scrolls.