and fills my soul with gratitude beyond expression

We need the Atonement of Jesus Christ, because we are all hard hearted and in a lost and fallen state. Alma 34:9  When Adam fell, humans became subject to physical death, the separation of the body and the spirit (Moses 6:48). Because no unclean thing can enter the presence of the Father, sin is spiritual death; it separates us from God. (1 Nephi 10:21). We cannot overcome the chains of physical or spiritual death without the Atonement (John 3:16; 2 Nephi 2:5–9).

Because of the Savior’s atoning sacrifice, all will be resurrected, overcoming physical death (Mosiah 16:7–8). In atoning, He took our sins. This gives us the opportunity to repent and be forgiven,  allowing us to become clean and worthy to dwell with God (Alma 7:13–14; Articles of Faith 1:3). In the Garden, he took upon himself the infirmities of all mankind. through this experience Jesus understands our difficulties and how to help us (Alma 7:11–12). "Learn of me, and listen to my words; walk in the meekness of my Spirit, and you shall have peace in me." D&C 19:23

“It took the atonement of Jesus Christ to reunite the bodies and spirits of men in the resurrection. And so all the world, believers and non-believers, are indebted to the Redeemer for their certain resurrection, because the resurrection will be as wide as was the fall, which brought death to every man. There is another phase of the atonement which makes me love the Savior even more, and fills my soul with gratitude beyond expression. It is that in addition to atoning for Adam’s transgression, thereby bringing about the resurrection, the Savior by his suffering paid the debt for my personal sins. He paid the debt for your personal sins and for the personal sins of every living soul that ever dwelt upon the earth or that ever will dwell in mortality upon the earth. But this he did conditionally. The benefits of this suffering for our individual transgressions will not come to us unconditionally in the same sense that the resurrection will come regardless of what we do. If we partake of the blessings of the atonement as far as our individual transgressions are concerned, we must obey the law. … When we commit sin, we are estranged from God and rendered unfit to enter into his presence. No unclean thing can enter into his presence. We cannot of ourselves, no matter how we may try, rid ourselves of the stain which is upon us as a result of our own transgressions. That stain must be washed away by the blood of the Redeemer, and he has set up the way by which that stain may be removed. That way is the gospel of Jesus Christ. The gospel requires us to believe in the Redeemer, accept his atonement, repent of our sins, be baptized by immersion for the remission of our sins, receive the gift of the Holy Ghost by the laying on of hands, and continue faithfully to observe, or do the best we can to observe, the principles of the gospel all the days of our lives” (Marion G. Romney, Conference Report, Oct. 1953, 35–36).