In English, the possessive pronoun is not usually repeated in lists. In Hebrew however, the possessive pronoun is repeated each time. The Book of Mormon contains many examples of this Hebraism, as Donald W. Parry explains:
In lists the Hebrew language repeats the possessive pronoun (e.g., their, our, your, thy, his, her) before each of the nouns to which it refers, a convention that is uncommon in English usage. The Old Testament (Hebrew Bible) preserves many examples of this Hebrew usage. For instance, the pronoun our is used six times in the King James Version of Exodus 10:9: “And Moses said, We will go with our young and with our old, with our sons and with our daughters, with our flocks and with our herds will we go” (emphasis added). Other biblical examples include the repetition of our five times in Deuteronomy 26:7, their four times in Genesis 10:20, your five times in Exodus 12:11, your four times in Leviticus 26:30, and our six times in Nehemiah 9:32.
Many examples of this usage appear in the Book of Mormon. For instance, the possessive pronoun your is used twelve times in 3 Nephi 30:2:
Turn, all ye Gentiles, from your wicked ways; and repent of your evil doings, of your lyings and deceivings, and of your whoredoms, and of your secret abominations, and your idolatries, and of your murders, and your priestcrafts, and your envyings, and your strifes, and from all your wickedness and abominations, and come unto me, and be baptized in my name, that ye may receive a remission of your sins, and be filled with the Holy Ghost. (emphasis added)
Other examples of the repeated possessive pronoun in the Book of Mormon include your four times in Mosiah 4:30, their eight times in Mosiah 11:3, your three times in Alma 32:42, our nine times in Alma 44:5, thy four times in Alma 38:3, and their twelve times in Helaman 3:14– Donald W. Parry, “Hebraisms and Other Ancient Peculiarities in the Book of Mormon,” in Echoes and Evidences of the Book of Mormon
How would Joseph Smith know about this Hebraism? Why would he repeat the possessive pronoun unless he was provided the words?