What is the Spirit of Elijah ?

In the Doctrine and Covenants 110:13-16 relates the visit of Elijah to the Kirtland Temple on 3 April 1836. This is how the visit was recorded:

13 After this vision had closed, another great and glorious vision burst upon us; for Elijah the prophet, who was taken to heaven without tasting death, stood before us, and said: 

14 Behold, the time has fully come, which was spoken of by the mouth of Malachi—testifying that he [Elijah] should be sent, before the great and dreadful day of the Lord come— 

15 To turn the hearts of the fathers to the children, and the children to the fathers, lest the whole earth be smitten with a curse— 

16 Therefore, the keys of this dispensation are committed into your hands; and by this ye may know that the great and dreadful day of the Lord is near, even at the doors.

This appearance of the Prophet Elijah was in partial fulfillment of the prophecy spoken of by the Angel Moroni at the time of his visit to Joseph Smith where he quoted Malachi 4:5-6 with some significant variations. Moroni's words are recorded in the Doctrine and Covenants 2:1-3:

1 Behold, I will reveal unto you the Priesthood, by the hand of Elijah the prophet, before the coming of the great and  dreadful day of the Lord.

2 And he shall plant in the hearts of the children the promises made to the fathers, and the hearts of the children shall turn to their fathers.

3 If it were not so, the whole earth would be utterly wasted at his coming.

Malachi 4:5-6 in the King James Bible says:

5 Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the Lord:

6 And he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse.

Quoting from the Teachings of the Prophet Joseph Smith at page 193:

This doctrine presents in a clear light the wisdom and mercy of God in preparing an ordinance for the salvation of the dead, being baptized by proxy, their names recorded in heaven and they judged according to the deeds done in the body. This doctrine was the burden of the scriptures. Those Saints who neglect it in behalf of their deceased relatives, do it at the peril of their own salvation. The dispensation of the fullness of times will bring to light the things that have been revealed in all former dispensations; also other things that have not been before revealed. He shall send Elijah, the Prophet, &c., and restore all things in Christ.

These special manifestations prepared the way for the Spirit of Elijah to do its work throughout the world. Elder Russell M. Nelson, in a talk entitled, “A New Harvest Time,” at the May 1998 General Conference, explained about the Spirit of Elijah:

With that [the restoration], natural affection between generations began to be enriched. This restoration was accompanied by what is sometimes called the Spirit of Elijah—a manifestation of the Holy Ghost bearing witness of the divine nature of the family. Hence, people throughout the world, regardless of religious affiliation, are gathering records of deceased relatives at an ever-increasing rate. (comment in brackets added for explanation).

The effect that this should have on each of us is well said by Elder Richard G. Scott in the 1990 General Conference in a talk entitled, "Redemption: The Harvest of Love."

I testify that the spirit of Elijah is touching the hearts of many of Father’s children throughout the world, causing the work for the dead to accelerate at an unprecedented pace.

But what about you? Have you prayed about your own ancestors’ work? Set aside those things that don’t really matter in your life. Decide to do something that will have eternal consequences. Perhaps you have been prompted to look for ancestors but feel that you are not a genealogist. Can you see that you don’t have to be anymore? It all begins with love and a sincere desire to help those who can’t help themselves.

This is a spiritual work, a monumental effort of cooperation on both sides of the veil where help is given in both directions. It begins with love. Anywhere you are in the world, with prayer, faith, determination, diligence, and some sacrifice, you can make a powerful contribution. Begin now. I promise you that the Lord will help you find a way. And it will make you feel wonderful.

This says very well much of my own motivation for working in the vast field of genealogy.