Moses warned the Pharaoh that unless the Israelites were freed, the Egyptians would be afflicted with sickness, pestilence, and ultimately the death of their firstborn sons (see Exodus 7–12). Each of these prophecies came to pass. The Pharaoh told Moses to leave Egypt with the Israelites and he parted the Red Sea so they could flee to safety.
The Old Testament prophet Jeremiah foretold the destruction of Jerusalem (see Jeremiah 25:2, 9–11). History records that the Babylonians did indeed demolish Jerusalem in 587 BC. The Book of Mormon prophet Lehi also warned people of Jerusalem's impending destruction. Because of this revelation he received from God, Lehi and his family fled Jerusalem. The history of him and his family is recorded in the Book of Mormon, another testament of Jesus Christ.
An apostasy is a period when God’s authority is not found on the earth. After Jesus was resurrected and ascended into heaven, His disciples knew He would one day return as He had said. However, the Apostle Paul taught that the Church Jesus established would fall away before Christ came again: “Let no man deceive you by any means: for that day shall not come, except there come a falling away first” (2 Thessalonians 2:3). This apostasy occurred in the centuries after Jesus’s original Apostles, who held His priesthood authority, died or were killed.
While God knew that His priesthood authority, prophets, and the full gospel of Jesus Christ would be gone from the earth for a time, He also promised that they would one day be reestablished. Peter in the New Testament promised that in the last days, there would come “the times of restitution [or restoration] of all things” (Acts 3:21). This restoration of Jesus's gospel began in 1820 when God called the Prophet Joseph Smith and restored His priesthood authority on the earth. Since The Church of Jesus Christ of Latter-day Saints was organized in 1830, it has been led by a living prophet.
The prophet Ezekiel revealed that the writings of the descendants of Judah (the Bible) and the writings of the descendants of Joseph (the Book of Mormon) would one day come together to unify His people in righteousness. “Moreover, thou son of man, take thee one stick, and write upon it, For Judah, and for the children of Israel his companions: then take another stick, and write upon it, For Joseph, the stick of Ephraim, and for all the house of Israel his companions: And join them one to another into one stick; and they shall become one in thine hand” (see Ezekiel 37:16–17). Both the Bible and the Book of Mormon teach us about God and Jesus Christ and how we can return to live with Them.