The Law of Witnesses - Mormon 8:1-6

1 BEHOLD I, Moroni, do finish the record of my father, Mormon. Behold, I have but few things to write, which things I have been commanded by my father.
2 And now it came to pass that after the great and tremendous battle at Cumorah, behold, the Nephites who had escaped into the country southward were hunted by the Lamanites, until they were all destroyed.
3 And my father also was killed by them, and I even remain alone to write the sad tale of the destruction of my people. But behold, they are gone, and I fulfil the commandment of my father. And whether they will slay me, I know not.
4 Therefore I will write and hide up the records in the earth; and whither I go it mattereth not.
5 Behold, my father hath made this record, and he hath written the intent thereof. And behold, I would write it also if I had room upon the plates, but I have not; and ore I have none, for I am alone. My father hath been slain in battle, and all my kinsfolk, and I have not friends nor whither to go; and how long the Lord will suffer that I may live I know not.
6 Behold, *four hundred years have passed away since the coming of our Lord and Savior.

(Book of Mormon | Mormon 8:1 - 6)

This passage is in line with the law of witnesses, i.e. “In the mouth of two or three witnesses shall every word be established.” 2 Corinthians 13:1

The original prophets wrote the record and Mormon abridged them, becoming a witness of them. Here we have his son Moroni also becoming a witness of the Book of Mormon.

Since Moroni was the person who gave the plates to Joseph Smith, there is a clear line of ownership and possession of the records. Joseph Smith fulfilled the law of witnesses with both the Three Witnesses and the Eight.

It is obvious that Mormon had this in mind. Moroni states that he was commanded by his father to finish the record.

I add my voice and witness to the Book of Mormon. I have read it dozens of times. I have felt the Spirit of the Lord bear witness to my soul that it is true. That knowledge fills me with a sense of peace and comfort. I know who I am, I am a son of God. I know why I am here. I know how to partake of the Tree of Life and receive Eternal Life. I am grateful for my testimony.

The best thing about the Book of Mormon is that there is no reason for you to take my word that it is true. You can find out for yourself. Sincerely read and ponder the Book of Mormon. As you do so, ask your Father in Heaven to know if it is true. He will answer your sincere prayer. He loves you and wants to help bring you home again.