Nephi quoted from Zenock, Neum, and Zenos. These were prophets of Old Testament times whose detailed prophecies of Jesus Christ were recorded on the brass plates; therefore we know they lived before 600 B.C. They spoke plainly about the life and ministry of the Messiah and the destiny of the house of Israel (see also Helaman 8:19–20). Without the Book of Mormon, we would know nothing about these three prophets or their witnesses of Christ.