What is the redemption? The redemption accomplished by Jesus Christ refers to the act by which Jesus obtained for all men the gift of salvation, or more specifically, putting them in a state in which they are able to receive that gift, because not everyone necessarily obtains that gift of salvation. The history of Christ's redemption actually begins with the story of creation.
Creation末The first verse of the Bible tells us that "In the beginning, God created the universe" (Genesis 1:1). The climax of God's creation was the making of man: "God took soil from the ground and formed a man; he breathed life giving-breath into his nostrils" (Genesis 2:7). God then took a rib from the first man, Adam, and formed the first woman, Eve (Genesis 2:22). Man was made in the image and likeness of God (Genesis 1:26), and as such, man has a spirit, a mind, and a will末more specifically, a free will. It was this free will, along with the devil, that led to the fall of man.
The Fall of the Angels末Besides creating man, God also created angels. God tested the angels, and out of pride, Lucifer, one of the brightest of the angels, rebelled against God: "War broke out in heaven. Michael and his angels fought against the dragon, who fought back with his angels, but the dragon was defeated, and he and his angels were not allowed to stay in heaven any longer. The dragon was thrown out; that ancient serpent, named the devil, or Satan, that deceived the whole world. He was thrown down to earth, and all his angels with him" (Revelation 12:7-9). Lucifer and his followers, who numbered one-third of the angels, were cast out of heaven and into hell: "The angels who did not stay within the limits of their proper authority . . . are bound with chains in the darkness below" (Jude 6). These angels are also called demons.
The Fall of Man末God bestowed upon Adam and Eve great gifts (CCC, 374-379), such as happiness in the Garden of Eden, control of their passions, a life without suffering and death, and most importantly, sanctifying grace, which gave their souls supernatural life, made their souls holy and pleasing to God, and gave them the right to enter heaven upon the completion of their earthly life. God put man in charge of the Garden of Eden, but with one stipulation: "You may eat the fruit of any tree in the garden, except the tree that gives knowledge of what is good and bad. You must not eat of the fruit of that tree; if you do, you will die the same day" (Gen. 2:16-17. The snake told Adam and Eve that they would not die if they ate of the fruit, but rather, "when you eat it, you will be like God" (Gen. 3:5). Adam and Eve were thus tempted by Satan, and they gave in by eating the forbidden fruit (Gen. 3:6). (The Catholic belief is that the story of Adam and Eve is an allegory釦he snake represents Satan, the fruit represents something that was forbidden by God, and "Adam" and "Eve" are the names that have been given to the first man and the first woman, these first parents that fell from grace; CCC 350).
Original Sin末Because of this first sin, Adam and Eve were punished (Gen. 3:16-19). They were thrown out of the Garden of Eden. They lost the gifts that were given to them. Instead of having control of their passions, temptations became very difficult to resist. Adam and Eve were susceptible to suffering and death. And most importantly, they lost sanctifying grace, and therefore lost the right to enter heaven. All of Adam and Eve's descendants inherited these punishments, which is referred to as "original sin" (CCC 404): "I was born guilty, a sinner, even as my mother conceived me" (Psalms 51:7). Man now had a fallen nature, and all men thereafter were born with a fallen nature: "By one man's disobedience [Adam], many [all, who number many] became sinners" (Romans 5:12); "In woman was sin's beginning, and because of her we all die" (Sirach 25:23).
The Incarnation末God could have just restored mankind to a state of grace by declaring it so, but the perfect justice of God demands satisfaction. However, nothing man did could satisfy or make up for his sinfulness. God gave Moses the Ten Commandments, but these laws could not save men because no man could keep the commandments perfectly (Jas. 2:10). These commandments were given to the Jews to show them that they were utterly lost and needed a savior. But the prophets predicted that God would send Israel a savior. In order to save mankind from eternal separation from God by reopening the gates of heaven, God sent His Son into the world. Gabriel said to Mary at the Annunciation: "You will conceive and give birth to a son . . . the Holy Spirit will come upon you . . . the holy child will be called the Son of God" (Luke 1:31,35). By the power of the Holy Spirit, God the Son, retaining His divine nature, took on a human nature as well by becoming a man (CCC 461).
The Redemption末 When Jesus suffered and died on the cross (Matthew 26:36-27:50), He offered His suffering and death as a sacrifice in satisfaction for the sins of all mankind. This act of love for man pleased the Father more than sin displeased Him, and He accepted this as a fitting sacrifice to redeem mankind, or purchase back the gift of grace that the first humans had lost. This sacrifice obtained sanctifying grace for all mankind, and all men who receive that grace have the right to enter heaven. God's death on the cross shows us the great love that God has for us, as well as the evil of sin. The soul of Christ descended to Limbo, the place where the righteous went before the gates of heaven were opened (1 Pet. 3:19), to preach the gospel to them. Three days after His death, Christ rose from the dead (John 20:9). He did this in order to prove to all that He was truly God, and to show us that all men will someday rise from the dead.