Jesus has taught us that there are "many mansions" in heaven:
- In my Father’s house are many mansions: if it were not so, I would have told you. I go to prepare a place for you. (John 14:2)
- Let not your hearts be troubled; for in my Father’s house are many mansions, and I have prepared a place for you; and where my Father and I am, there ye shall be also. (Doctrine and Covenants 98:18)
These scriptures could mean that there are literally many abodes where the Father himself dwells, and that there are many levels of heaven and many various realms of glory.
Three Heavenly Kingdoms
The Plan of Salvation as taught by The Church of Jesus Christ of Latter-day Saints (Mormonism) holds that Heaven is divided into three separate kingdoms of glory (each of which contains "many mansions). Mormons call these heavenly kingdoms the "Three Degrees of Glory:" the Celestial, the Terrestrial, and the Telestial. These kingdoms are where all men and women, with the exception of Sons of Perdition, who will go to Outer Darkness (also see Hell), will go after they are judged of God and resurrected (their spirits reunited with their then immortal bodies). Entrance into each kingdom depends on a person's worthiness and his adherence to the commandments of God and the ordinances He has prescribed. Since God is the ultimate judge, all people will be judged fairly and awarded the kingdom where they will be most happy and comfortable. The Doctrine and Covenants describes that men and women will be sent to "their own place, to enjoy that which they are willing to receive" (Doctrine and Covenants 88:32). Many people will be sent to the lower kingdoms "because they were not willing to enjoy that which they might have received" (Doctrine and Covenants 88:32), namely exaltation in the Celestial kingdom. Even so, all three kingdoms are kingdoms of glory and even the lowest is more glorious than man can currently comprehend.
Knowledge of the Three Degrees of Glory was given to Latter-day Saints by revelation directly from God through a vision given to Joseph Smith the Prophet and Sidney Rigdon, at Hiram, Ohio, February 16, 1832 (History of the Church 1: 245–252). Prefacing his record of this vision the Prophet wrote: “Upon my return from Amherst conference, I resumed the translation of the Scriptures. From sundry revelations which had been received, it was apparent that many important points touching the salvation of man had been taken from the Bible, or lost before it was compiled. It appeared self-evident from what truths were left, that if God rewarded every one according to the deeds done in the body, the term ‘Heaven,’ as intended for the Saints’ eternal home, must include more kingdoms than one. Accordingly, while translating St. John’s Gospel [chapter 5], myself and Elder Rigdon saw the following vision.” This vision is described in Doctrine and Covenants, section 76. 
- These are they whose names are written in heaven, where God and Christ are the judge of all.
- These are they who are just men made perfect through Jesus the mediator of the new covenant, who wrought out this perfect atonement through the shedding of his own blood.
- These are they whose bodies are celestial, whose glory is that of the sun, even the glory of God, the highest of all, whose glory the sun of the firmament is written of as being typical (Doctrine and Covenants 76:68-70).
- Wherefore, all things are theirs, whether life or death, or things present, or things to come, all are theirs and they are Christ’s, and Christ is God’s (Doctrine and Covenants 76:59).
The Celestial Kingdom is the highest and most glorious of the degrees of glory and is symbolically represented by the sun. It is this kingdom where God Himself reigns. It is understood that the Celestial Kingdom itself contains many degrees of glory. Anyone who inherits any degree of glory in the Celestial Kingdom dwells in God's presence.
According to revelation from the Lord, only those who have been married and sealed in the temple (whether in this life or vicariously or during the Millenium) can attain the very highest realm of the Celestial Kingdom. In agreement with the Apostle Paul's teaching that "neither is the man without the woman, neither the woman without the man, in the Lord" (1 Corinthians 11:11), Mormonism teaches that marriage is not only divinely instituted, but eternally necessary and significant. Neither a man nor a woman can attain the fullest exaltation by themselves. Mormonism also teaches that since not all people have the opportunity to marry in this life, opportunity will be given them during Christ's millennial reign after His Second Coming. Additionally, Mormonism teaches that only those in the highest realm of the Celestial Kingdom will remain married and be able to form an eternal family. These are those who have made eternal marriage covenants on earth, rather than covenants that cease with death.
Mormon doctrine also teaches that all children who die before reaching the age of accountability (age eight, when children are then better able to judge for themselves what is right and wrong) will be saved in the Celestial Kingdom (Doctrine and Covenants 137:10). Mormons also believe that all men and women "who have died without a knowledge of this gospel, who would have received it if they had been permitted to tarry, shall be heirs of the celestial kingdom of God;" as well as "all that shall die henceforth without a knowledge of it, who would have received it [the Gospel] with all their hearts, shall be heirs of that kingdom" (Doctrine and Covenants 137:7-8).
Except for little children, those who hope to prove worthy of eternal life in any of the mansions of the Celestial Kingdom must meet the following qualifications found in Doctrine and Covenants 76:50-53:
- Receive and be valiant in a testimony of Jesus Christ
- Be baptized in the name of Christ
- Receive the Gift of the Holy Ghost
- Obey the commandments of God
- Be washed and cleansed from all sins
- Overcome by faith and endure to the end
- Be sealed by the Holy Spirit of Promise
President James E. Faust of the First Presidency explained that "to have a covenant or ordinance sealed by the Holy Spirit of Promise means that the compact is binding on earth and in heaven." (“The Gift of the Holy Ghost—A Sure Compass,” Ensign, May 1989, 31.)
The necessity of making covenants and receiving ordinances in the flesh is the reason Mormons practice Baptism for the Dead, eternal marriage, and sealing covenants for the dead in their temples. Baptisms for the dead are not performed for children who died under the age of 8. The gospel is preached in the Spirit World to deceased persons who have not yet been resurrected. If the saving ordinances have been done for them on earth by proxy, they can choose whether or not to accept them.
The location of the Celestial Kingdom will be here on earth after the earth is changed. Its final destiny is to become glorified and exalted (Doctrine and Covenants 77: 1-2; 130: 8-9). The earth will become an eternal inheritance of those who have lived worthy of a celestial glory (Doctrine and Covenants 88: 14-26). They will enjoy the presence of the Father and the Son (Doctrine and Covenants 76: 62).
- These are they who receive of his glory, but not of his fulness.
- These are they who receive of the presence of the Son, but not of the fulness of the Father.
- Wherefore, they are bodies terrestrial, and not bodies celestial, and differ in glory as the moon differs from the sun.
- These are they who are not valiant in the testimony of Jesus; wherefore, they obtain not the crown over the kingdom of our God (Doctrine and Covenants 76:76-79).
The Terrestrial kingdom is symbolically represented as the moon. It is related to the moon because although it does not give forth as much light as the sun (Celestial), it gives more light (when viewed from earth) than the stars (Telestial). While people in the Terrestrial kingdom receive of God's glory, they cannot receive of His fullness or dwell eternally in His presence.
People will inherit the Terrestrial Kingdom for the following reasons (see Doctrine and Covenants 76:72-79):
- They died without law.
- They received a testimony of Christ after this life (See Spirit World), but had rejected it while on the earth.
- They were honorable people who allowed themselves to be blinded by the wickedness of the world.
- They were not valiant in their testimonies of Jesus Christ.
The Spirit World is located here on earth in what could be termed another dimension. At times when the veil is thin, we can see the spirits in the Spirit World through the veil.
- These are they who say they are some of one and some of another—some of Christ and some of John, and some of Moses, and some of Elias, and some of Esaias, and some of Isaiah, and some of Enoch;
- But received not the gospel, neither the testimony of Jesus, neither the prophets, neither the everlasting covenant.
- Last of all, these all are they who will not be gathered with the saints, to be caught up unto the church of the Firstborn, and received into the cloud.
- These are they who are liars, and sorcerers, and adulterers, and whoremongers, and whosoever loves and makes a lie.
- These are they who suffer the wrath of God on earth (Doctrine and Covenants 76:100-104).
In Mormonism the glory of the Telestial Kingdom is compared to that of the stars. People who are sent to the Telestial Kingdom will be the last to be resurrected and cannot dwell where God and Christ live. This final resurrection will take place after the Millennium.
According to the Doctrine and Covenants those who will inherit this kingdom are those who:
- Rejected the gospel, the testimony of Jesus, the prophets, and the everlasting covenant.
- Were liars, adulterers, murderers, thieves, and all others who flouted God's commandments.
Progression Between Kingdoms
A common question asked by members is whether it is possible for someone to eventually move from Telestial to Terrestial glory, or, relatedly, from Terrestial to Celestial glory. Some even compare it to wheels on a train. You may get where someone ahead of you was before, but they will always be ahead of you.
General Authorities Bruce R. McConkie (in Seven Deadly Heresies), Spencer W. Kimball (in Miracle of Forgiveness), and Joseph Fielding Smith (in Doctrines of Salvation) have stated that once someone is within a kingdom of glory, that person remains within that kingdom for all eternity; no one can advance out of a kingdom. Many general authorities do speculate that there is advancement within kingdoms, though.ru:Целестиальное, Террестриальное и Телестиальное Царства