Why Members of the Church of Jesus Christ of Latter-day Saints do Temple Work

If you desire to know why members of the Church of Jesus Christ of Latter-day Saints do work for their ancestors in their temples, please consider the following basic information which explains why they do it.

1. All human beings are children of a God who loves them. All humans are brothers and sisters to each other, begotten by a Father in Heaven who is good and great, who knows all things and controls all things in this universe. As a kind and wise Father, he wishes to share all that he has and is with each of his children. If those children are willing to become good and great, kind and wise as he is, then he can share all he is and does with each one. What our Father is and does makes him happy, and he desires that all of his children become as happy as he is. Our Father will see that each of his human children is as happy as he or she can stand to be for the rest of eternity.
2. Our Father has a plan to help each human being become as good and great, as kind and wise as he is. That plan of happiness is known as the Gospel of Jesus Christ. Part of this plan was that Jesus Christ would be sent to teach each of Father’s children how to become good and great, kind and wise. The gospel plan is that we should each put our trust in Jesus Christ (have faith in him), change our ways of acting to act as Christ acts (repentance), make a covenant to gain the character of Jesus Christ (promise in baptism to become good and great, kind and wise as he is), receive his personal guidance as to how to transform our lives (by receiving the Holy Ghost, the personal messenger of the Father and the Son Jesus Christ), and follow the guidance until our character achieves the measure of the stature of the fullness of Jesus Christ (enduring to the end).
3. Our Father knows that we cannot become as he is and like Jesus Christ, who is already like him, unless we have more knowledge and power than do ordinary human beings. That is why he offers his children the companionship of the Holy Ghost, so that the Holy Ghost can teach us all good things. Father offers his children the Holy Priesthood so that we can gain the power to do all the things that he, our Father, and our Savior, Jesus Christ, do. That power comes through accepting ordination to the Holy Priesthood after the order of Melchizedek and learning to use that power in pure love. The fullness of that priesthood is given only in the blessings of the Holy Temples of God, which temples have been dedicated and consecrated by the power of the Holy Melchizedek Priesthood possessed by the prophets of God on the earth who have been sent by Jesus Christ to represent him in these latter days.
4. Those who accept the Gospel of Jesus Christ and live it, and who accept the fullness of the Holy Melchizedek Priesthood and magnify that priesthood, and who learn to bless others as Christ idid in his mortal ministry, have accepted the opportunity to rise to the full stature of Jesus Christ.
5. They will have done this through faith in Jesus Christ, repenting of every sin, and enduring to the end. One of the things a person will do as they become like Jesus Christ is to want to share all of the good things they have with others of their human brothers and sisters. This is why they become missionaries, so they can share the good news about Jesus Christ and Father’s plan with other human beings. This is why they do temple work for their ancestors, so that they can share the fullness of the Melchizedek Priesthood and its power with other human beings. This is why they minister to their neighbors in love, kindness and power. This missionary work, temple work and ministering is the spreading blessings and the plan of happiness, for every child of God was born to become blessed and happy.
6. Because our Father does love us so much, he sent his Son, Jesus Christ, to be a mortal on this earth and to teach all human beings by both precept and example what it means to be good and great, kind and wise. Christ did this and was great by being the servant of all  mankind. He showed us how to react to evil, how to bless others, how to teach the truth, how to live a holy life. But the greatest thing Jesus Christ did for each human being was to suffer for the sins of each person and to die for each person. This great unparalleled act of atoning love makes it possible for Father to forgive all men their sins (transgressions against their neighbors) which they have committed but have repented of doing, and to make it possible for every human to be resurrected after mortal death into a glorious and eternal body. Because Jesus Christ did this great thing to save all mankind from sinning and from the penalty of justice that follows sinning, and from never-ending death in an earthly grave, he is called our Savior. He, Jesus Christ, desires that all of his faithful disciples become like him, to love with a pure love as he does, and to become saviors also. This was prophesied by Obadiah when he spoke of the latter days: “And saviours shall come up on mount Zion to judge the mount of Esau; and the kingdom shall be the Lord’s.” (Obadiah 1:21)
7. To become as our Savior and to do a work of pure love, even as Christ would and did, Latter-day Saints offer to their departed ancestors the full power to become like Christ, by helping them to receive in Holy Temples the blessings of the Holy Melchizedek Priesthood they did not gain while mortal. As those ancestors accept and live in the world of the departed spirits the gospel of Jesus Christ and also accept and live up to the opportunities afforded by the fullness of the Holy Priesthood, they also can be ready when the kingdoms of this world will become the Kingdom of Christ at his second coming. Which is near, even at the door.