The statement of the Lord to Joseph who was sold into Egypt concerning the writings of Judah and "the fruit of thy loins" (2 Nephi 3:12) is very similar to the statement of the Lord to Ezekiel concerning the "sticks" of Judah and Joseph (Ezekiel 37:15-22). When these two references are read together, it is clear that the "stick of Judah" is the Bible, whereas the "stick of Joseph" is the Book of Mormon.
In connection with the Book of Mormon's being the stick of Joseph, it is important to note that Lehi was a direct descendant of Joseph through Manasseh, Joseph's son. (Alma 10:3.) It is also reported by Erastus Snow that Joseph Smith said Ishmael was a descendant of Joseph through his other son, Ephraim. (Journal of Discourses, 23:184-85.) Thus the people of Lehi's colony were pure Josephites, and their record rightfully qualifies as part of the "stick of Joseph."