The Ordinances of the Temple were instituted by the Lord in the New Testament, as they were originally in the days of Adam, and will be the means of saving all who desire to come unto Christ. These consist of the Endowment and Initiatory ordinances, the Sealing Ordinances, and Baptism for our deceased ancestors.
First, about the Endowment, Brigham Young has said, “Your endowment is, to receive all those ordinances in the house of the Lord, which are necessary for you, after you have departed this life, to enable you to walk back to the presence of the Father, … and gain your eternal exaltation.” Brigham Young in Discourses of Brigham Young, sel. John A. Widtsoe (1941), 416.
The Endowment is spoken of in the New Testament, where the Savior, after he was resurrected and before sending the apostles out to teach, said to "tarry ye at Jerusalem, until ye be endued with power from on high." (Luke 24:49). Interesting to note, this pattern of endowing people with power from on high is still followed in the church today, as those called as missionaries go through the endowment before going to serve.
going into specifics, all of the covenants we make in the Initiatory and Endowment, and indeed all of the ordinances of the temple,
have their genesis in the teachings of Christ, or his word revealed to
Old Testament and New Testament Prophets.
The sealing ordinances have biblical support as well. Though we see evidence of it in the Old Testament, we focus here on Christ's ministry. After Peter declared that Jesus was the Christ, The Savior said to him "And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven." (Matthew 16:19).
That is what happens in Temples. This power to bind on earth and in heaven was restored to the prophet Joseph Smith and recorded in the Doctrine and covenants multiple times (D&C 127:7, D&C 124:93, D&C 132:46, D&C 128). Families can be sealed to each other and to Christ for time and for all eternity, to become joint-heirs with Christ, as promised by Paul the evangelist in Romans 8.
Additionally, Baptisms for the dead were spoken by Paul, who said "Else what shall they do which are baptized for the dead, if the dead rise not at all? why are they then baptized for the dead?" (1 Corinthians 15:29). In this modern era, this ordinance is done as it was done in the New Testament church, so that our ancestors who never heard the gospel, or those who never heard of Christ can return to the presence of the Lord. For the Savior said all must be baptized in John 3:5, when he said "except a man be born of water and of the spirit, he cannot enter the kingdom of heaven."
All of these ordinances are indeed performed for those of our kindred dead who have not had the opportunity to receive them for themselves. This is done by proxy. We do the ordinances, and they, in the spirit world, are given the choice to accept or reject these ordinances. Most do, having been taught the principle of proxy ordinances, and in their spirit form, accept these saving ordinances so they can return to the presence of the Lord. More about this on this LDS Website link.
We are told in modern revelation that these same ordinances were given to Adam, and later to Abraham. For more on this topic, see this Search Page.
Because of the miracle of the Restoration of the Gospel, the sacred temple ordinances the Savior established in New Testament times, and back in the time of Adam, have been restored to this earth to bless our Father in Heaven's children. With the miracle of temple work, all of Father in Heaven's children who have ever lived on the earth, and who would have accepted it if they were alive, will be able to have the opportunity to accept or reject those blessings, and inherit all that our Father in Heaven has. And these blessings were spoken of in the Bible.
Finally, for us, when we go to the temple to do the work of our dead, we are able to feel of God's presence. The Doctrine and Covenants states "my glory shall rest upon it; Yea, and my presence shall be there, for I will come into it..." (D & C 97:15-16)
The spirit in temples is stronger than in any other place on earth, and if we are worthy, we can feel of the presence of the Lord as we complete these sacred ordinances for our ancestors that are necessary for them to return to the presence of God.
In Temples, we see the Saving Power of Christ. What mercy he has, that he offers all the chance to come unto him, even if they had never heard of him when alive. We have a role to play in that, as we attend the temple to do work for those who have gone on before us. We are told in Modern Revelation that the work of the Dead will be accelerated in the Millenium, when Christ himself will rule and reign and will oversee the completion of this great work.
May we ever be grateful to Christ, and come unto him in his holy house as we engage in this saving work, is my prayer.
Want to find out more about Christ? The Book of Mormon, along with the Bible, is the Word of God. I know it to be true. God Showed prophets what to include in the Book of Mormon for our day. Read the Promise of the Book of Mormon online now at http://bit.ly/10t8QYm or get a free copy at http://bit.ly/11WKJ1G
Questions? Click here to chat online http://bit.ly/14NQosW or, to meet with representatives from the Church of Jesus Christ of Latter-Day Saints, go to http://bit.ly/10t9mW7
Picture of the Provo City Center Temple courtesy of LDS Temple Pics