When King Benjamin was speaking in Mosiah 4 verse 3 it reads that the Spirit of the Lord came upon the them and they were filled with joy, having received a remission of their sins. I just want to know how can they have remission of their sins if Christ hasn’t been born yet. I am a member and I have read the Book of Mormon a few times. I would just like clarification. Thank you.
Your question is one many have had, and in the October 1996 General Conference, then Elder Russell M. Nelson spoke about the Old Testament practice of animal sacrifice and its limits, since the sacrifices were offered continuously:
In preparatory times of the Old Testament, the practice of atonement was finite—meaning it had an end. It was a symbolic forecast of the definitive Atonement of Jesus the Christ. His Atonement is infinite—without an end. It was also infinite in that all humankind would be saved from never-ending death. It was infinite in terms of His immense suffering. It was infinite in time, putting an end to the preceding prototype of animal sacrifice. It was infinite in scope—it was to be done once for all. And the mercy of the Atonement extends not only to an infinite number of people, but also to an infinite number of worlds created by Him. It was infinite beyond any human scale of measurement or mortal comprehension.
Jesus was the only one who could offer such an infinite atonement, since He was born of a mortal mother and an immortal Father. Because of that unique birthright, Jesus was an infinite Being.
Alma’s son Corianton. In Alma 39’s chapter heading we read that “Christ’s redemption is retroactive in saving the faithful who preceded it.” The relevant verses, 17-19, read,
And now I will ease your mind somewhat on this subject. Behold, you marvel why these things should be known so long beforehand. Behold, I say unto you, is not a soul at this time as precious unto God as a soul will be at the time of his coming?
Is it not as necessary that the plan of redemption should be made known unto this people as well as unto their children?
Is it not as easy at this time for the Lord to send his angel to declare these glad tidings unto us as unto our children, or as after the time of his coming?
In 2 Nephi 9:7 Jacob describes the atonement of Jesus Christ as “infinite” and it truly is, not only effective for all mankind, but also through all time. A few verses later from the one you referenced in Mosiah 4, verses 6 and 7, King Benjamin states the atonement was prepared from the foundation of the world. Recall how in the Grand Council in Heaven, Christ stepped up to carry out the Father’s Great Plan of Happiness. He would accomplish His Father’s work and since it is an infinite atonement, it applies to “all who would ever live upon the Earth.” (The Living Christ, the Testimony of the Apostles).