Knowledge of two great truths is essential to understanding the Atonement of Jesus Christ. A person must realize that there was a fall of Adam and thus all mankind, and that Jesus Christ was the son of God the Father. Because of Jesus’ great love for all mankind, He would do something for them that they could not do for themselves. Jesus would come to this earth to atone for the transgressions of mankind and freely give His life and then break the bands of death through His own resurrection.
Adam and Eve were immortal while living in the Garden of Eden. Once they took of the fruit of knowledge of good and evil, they were no longer permitted to live in the Garden of Eden, and became mortal (Genesis 3:3). Adam and Eve were now subject to illness, pain, and eventually death.
The Apostle Paul refers to another death. This is spiritual death, which comes from sin (Romans 6:23). Jesus commanded “Be ye therefore perfect, even as your Father which is in heaven is perfect” (Matt 5:48). We learn from these scriptures that we are spiritually unclean from sin, but that we must become perfect (whole, complete) like Heavenly Father and Jesus Christ.
Jesus could not die or be killed without allowing it. Because of His great love for all, He would pay the price of suffering for the transgressions of all people. He began this when He went to the Garden of Gethsemane and completed it upon the cruel cross of Calvary. (See Mark 14:32-34.)
In suffering the Atonement, because of Jesus Christ’s great and perfect love for all humankind, He voluntarily experienced all of their mortal infirmities and sicknesses as well. This suffering would allow Him to understand perfectly the emotions, feelings, and behavioral circumstances related to all transgressions and types of physical suffering that all mortals on this earth could experience.
Included with His Atonement would be another act of love, voluntary death. His great love for all was the leading factor for completing His atoning sacrifice or crucifixion and freely offer His life.
The Savior needed to die so that He could later break the bands or power of death effective upon all previous, current, and future dead of the human family. He did what only He could do, take up his body after death and become a living, immortal being. Through His resurrection and by becoming the firstfruits of all the dead (1 Corinthians 15:23), the Savior opened up the way for the entire human race to gain salvation and regain their former physical bodies, never to suffer physical death again.
In performing the atonement, Jesus provided us a way to overcome the effects of 'original sin' --from the sin of Adam and Eve. Jesus overcame the Fall. We are liable for our own sins and must repent in order to call on the effects of the Atonement, but are not responsible for Adam's sin.