FairMormon is a non-profit organization dedicated to providing well-documented answers to criticisms of LDS doctrine, belief and practice.
In Alma 46 we read that the Nephite chief captain Moroni tore out a piece of his garment, wrote a motto on it, and mounted it as a standard to rally his troops. Soldiers dressed in their armor ran to him, "rending their garments . . . as a covenant" that if they should forsake God, "the Lord should rend them even as they had rent their garments" (Alma 46:21). They then "cast their [rent] garments at the feet of Moroni" as a sign that if they should "fall into transgression," God might "cast us at the feet of our enemies, even as we have cast our garments at thy feet to be trodden under foot" (Alma 46:22).
Taking his cue from this act, Moroni then exhorted his people, referring to them as "a remnant of the seed of Joseph, whose coat was rent by his brethren into many pieces" and citing the words of Joseph's father, Jacob, who, "before his death . . . saw that a part of the remnant of the coat of Joseph was preserved and had not decayed. And he said—Even as this remnant of garment of my son hath been preserved, so shall a remnant of the seed of my son be preserved by the hand of God, and be taken unto himself" (Alma 46:23, 24).
The biblical account in Genesis 37 indicates that Joseph's brothers stripped him of his garment and later dipped it in goat's blood to make it appear that he had been slain by a wild beast (see Genesis 37:23, 31). It does not say that they tore the garment, though Jacob, upon seeing it, said that Joseph had been "rent in pieces" by some wild beast (Genesis 37:33).
Aside from Alma 46:23, the only document I know of that clearly indicates that the brothers tore Joseph's garment is the thirteenth-century collection of earlier Jewish stories known as the Book of Jasher: "And they hastened and took Joseph's coat and tore it, and they killed a kid of the goats and dipped the coat into the blood of the kid, and then trampled it in the dust, and they sent the coat to their father Jacob" (Jasher 43:13). One cannot fail to note the parallel with Moroni's soldiers, who cast their garments down "to be trodden under foot" (Alma 46:22). Since the Book of Jasher did not come to Joseph Smith's attention until it was published in English in 1840, it seems that this medieval Jewish document shares an ancient tradition also found in the Book of Mormon.
The preservation of Joseph's garment is noted in the Zênâhu La-Yosêf, an Ethiopic manuscript from the Dabra Bizon monastery, in which Benjamin, eating with the Egyptian official he did not yet know to be his brother Joseph, told him of his lost brother and of his father Jacob's mourning: "He looks at his [Joseph's] garment stained in his blood. He puts it in front of him, and soaks it every day with the tears of his eyes."20 According to a Muslim tradition reported by al-Kisa'i, Jacob, before sending his sons to Egypt for the second time, gave "Joseph's shirt to Benjamin to wear, the one that had been brought to him spattered with blood."21
According to Alma 46:24, it was the preservation of a remnant of Joseph's garment that led Jacob to exclaim, " . . . so shall a remnant of the seed of my son be preserved by the hand of God." A similar story is found in early Jewish and Muslim traditions, which vary in that it was a second garment, brought to Joseph by the angel Gabriel, that gave Jacob to know that Joseph had been preserved.22 According to al-Kisa'i, after revealing his identity to his brethren, Joseph "took off the shirt that God had given him in the well and gave it to Judah, saying, 'Depart ye with this my inner garment, and throw it on my father's face; and he shall recover his sight.'"23 When Judah was yet ten days' distance from his father's camp, Jacob declared, "I perceive the smell of Joseph" and knew that his son was yet alive.24 Al -Tabarî's account also includes the tale of Joseph's sending his garment to heal his father's blindness and of Jacob's smelling "the scent of Joseph" before Judah arrived.25With so many details of the story told in Alma 46 reflected in early Jewish and Muslim texts, the suggestion that the Book of Mormon account reflects an ancient tradition seems inescapable.