In Biblical times, the people of Israel were given the Law of Moses, a specific code of commandments and ordinances to be followed. This Law was given to the people by a prophet to guide them and help them be better prepared to follow Jesus Christ when He came. It was never intended to be the law forever, but was a preparatory motion for the people of Israel. When Christ came to the Earth and completed the Atonement through His suffering, Crucifixion, and Resurrection, He overcame death of the body and set forth a new law.
In the Book of Mormon, Jesus tells the people "Behold, I am he that gave the law, and I am he who covenanted with my people Israel; therefore, the law in me is fulfilled, for I have come to fulfill the law; therefore it hath and end" (3 Nephi 15:5). He then introduced the doctrine of Christ, the higher law, saying: "I am the law, and the light. Look unto me, and endure to the end, and ye shall live; for unto him that endureth to the end will I give eternal life" (v. 9). This doctrine shows the way to return to Christ by having faith, repenting of our sins, being baptized for a remission or cleansing of these sins, receiving the gift of the Holy Spirit to be with us always, and enduring through life's inevitable struggles faithfully by following the commandments of God. I know that this gospel that Jesus Christ set forth is true, and although much of it was lost or confused as history went on after His death, the fullness of the gospel has been restored to the Earth through the prophet Joseph Smith. I testify that we can all look to Christ and follow His gospel as we learn to have faith, be obedient, and open our hearts to the truth that He has brought to the Earth through His servants, the prophets.