The Ordinance of Baptism for the Dead “Belongeth to My House”
Doctrine and Covenants 124:29–32
29 For a baptismal font there is not upon the earth, that they, my saints, may be baptized for those who are dead—
30 For this ordinance belongeth to my house, and cannot be acceptable to me, only in the days of your poverty, wherein ye are not able to build a house unto me.
31 But I command you, all ye my saints, to build a house unto me; and I grant unto you a sufficient time to build a house unto me; and during this time your baptisms shall be acceptable unto me.
32 But behold, at the end of this appointment your baptisms for your dead shall not be acceptable unto me; and if you do not these things at the end of the appointment ye shall be rejected as a church, with your dead, saith the Lord your God.
Elder D. Todd Christofferson said:
“The doctrine that the living can provide baptism and other essential ordinances to the dead, vicariously, was revealed anew to the Prophet Joseph Smith. He learned that the spirits awaiting resurrection are not only offered individual salvation but that they can be bound in heaven as husband and wife and be sealed to their fathers and mothers of all generations past and have sealed to them their children of all generations future. The Lord instructed the Prophet that these sacred rites are appropriately performed only in a house built to His name, a temple.”
(“The Redemption of the Dead and the Testimony of Jesus,” Ensign, Nov. 2000, 9.)