Mormon is a historian of the sacred, recording and emphasizing the sacred patterns of the past so that they may inform the future. It is therefore completely fitting that, as he bears his testimony, he uses connections to the past to proclaim the truth to his future readers. He begins this personal testimony by repeating his name. He dos not state “I am Mormon” because he thinks we need the reminder. Rather he is invoking his name in a formulaic benediction of his efforts. In the ancient world, one’s name was a powerful bond of one’s presence and identity. (See commentary accompanying 3 Nephi 13:7.)
In addition to declaring his name, he also declares his lineage. A man of the ancient world was not only an individual but also a representative of the kinship line that produced him. Hence, it is important for Mormon to assert that he is “a pure descendant of Lehi.” The connection of the present to the past is made in the last sentence, where Mormon links the fathers to his current effort. There is no context to help us determine the difference between a “pure descendant of Lehi” and a “not-pure descendant of Lehi.” The most conservative reading would be that Mormon is declaring a lineage that connects him directly to Lehi (logically through a part of the family that followed Nephi rather than Laman). In the logical context of the New World, there would have been many political Nephites who had no lineage connection to the original Lehi.