We need not expect to do this vast work for the dead in a short time.

As the Saints moved forward with this sacred work, “it soon became apparent that some had long records of their dead, for whom they wished to administer,” recalled Elder George A. Smith, a member of the Quorum of the Twelve. “This was seen to be but the beginning of an immense work, and that to administer all the ordinances of the Gospel to the hosts of the dead was no light task. Some of the Twelve asked Joseph if there could not be some shorter method of administering for so many. Joseph in effect replied: ‘The laws of the Lord are immutable; we must act in perfect compliance with what is revealed to us. We need not expect to do this vast work for the dead in a short time.’”

Chapter 41: Becoming Saviors on Mount Zion, Joseph Smith, Teachings of Presidents