In a court of law, a witness is asked to testify as to what he or she knows according to what has been seen and experienced. Do we know Jesus Christ well enough that we could stand as a witness of him? Those who knew the Savior best were called to be his apostles, special witnesses of Him to testify to all the world. We read of them in God's holy writ. For centuries, God's word was collected and passed down as scrolls. Jesus himself studied and read them as he grew. In his ministry he taught from and quoted the prophesies concerning his coming. These scrolls, together, now form what we know to be the Old Testament. In Jesus' day, those who knew the savior best recorded his words, his actions and his miracles from their first hand accounts. Those were written down as were the scrolls or "books" of the Old Testament. Several hundred years after Jesus' death, they were compiled into one book which we now recognize as the "New" Testament. The Old Testament witnesses of the promise of a Messiah, given to ancient Israel. The people were given laws through the Prophet Moses to point them towards Christ. When Jesus came to earth he fulfilled the law of Moses. The New Testament witnesses of his great atoning sacrifice, of his glorious resurrection and his abounding love for all mankind. Together, they form the Bible. They both witness of the covenant that God made with his people. 
The Book of Mormon is the spiritual account of a civilization that left Jerusalem 600 years before Christ's birth, led by a prophet of God. They crossed the ocean and settled on the American Continent. They too lived the law of Moses. After the death and resurrection of the Savior, Jesus came and appeared to them. Like the apostles of old to whom Jesus appeared and who felt the marks in his hands and in his feet, these people also witnessed of their experience. It is recorded:
"And it came to pass that the multitude went forth, and thrust their hands into his side, and did feel the prints of the nails in his hands and in his feet; and this they did do, going forth one by one until they had all gone forth, and did see with their eyes and did feel with their hands, and did know of a surety and did bear record, that it was he, of whom it was written by the prophets, that should come. And when they had all gone forth and had witnessed for themselves, they did cry out with one accord, saying: Hosanna! Blessed be the name of the Most High God! And they did fall down at the feet of Jesus, and did worship him" (3 Nephi 11:15-17).
We have this additional witness of the Savior because God speaks to man today. As He did with Moses, God appeared to the boy Joseph Smith in the year 1820. He sent to him angelic messengers as he did to Mary and to Joseph and to Jesus himself (see my post Angels). He was shown where the record of this people had been hidden. By the power of God, Joseph translated the record which is now known as The Book of Mormon. Hand in hand with the Old and the New Testament, it is Another Testament of Jesus Christ. I testify that it is true. I have felt the spirit of the Lord, confirm its veracity to me in my mind and in my heart. I have grown to know my Savior through reading its words and living its teachings.
Said the Prophet Joseph Smith, "I told the brethren that the Book of Mormon was the most correct of any book on earth, and the keystone of our religion, and a man would get nearer to God by abiding by its precepts, than by any other book." I invite all to examine, read and experience for themselves this record. I invite all to know Christ for themselves. For more information, please visit http://mormon.org/book-of-mormon/.
