Henry B. Eyring, of the Quorum of the Twelve Apostles, of the Church of Jesus Christ of Latter-Day Saints discusses this question during the April 2005 General Conference which was held in SLC, Utah, USA.
It is important to know why the Lord promised to send Elijah. Elijah was a great prophet with great power given him by God. He held the greatest power God gives to His children: he held the sealing power, the power to bind on earth and have it bound in heaven. God gave it to the Apostle Peter. And the Lord kept His promise to send Elijah. Elijah came to the Prophet Joseph Smith on April 3, 1836, just after the dedication of the Kirtland Temple, the first temple built after the Restoration of the gospel. Joseph described the sacred moment.“Hearts Bound Together,” Ensign or Liahona, May 2005, 78
Eyring then quotes Joseph Smith’s account of “visions manifested to Joseph Smith the Prophet and Oliver Cowdery in the temple at Kirtland, Ohio, April 3, 1836” as recorded in Doctrine and Covenants 110. This experience describes “Elijah’s return and he commits the keys of his dispensation as promised by Malachi” (see Doctrine and Covenants 110).
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:Doctrine and Covenants 110:13–16
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.
What did Elijah restore?
President Henry B. Eyring said: “It is important to know why the Lord promised to send Elijah. Elijah was a great prophet with great power given him by God. He held the greatest power God gives to His children: he held the sealing power, the power to bind on earth and have it bound in heaven” (“Hearts Bound Together,” Ensign or Liahona, May 2005, 78).See Come Follow Me, January 11–17
Doctrine and Covenants 2; Joseph Smith—History 1:27–65 “The Hearts of the Children Shall Turn to Their Fathers”
See also Doctrine and Covenants 110:13–16; David A. Bednar, “Let This House Be Built unto My Name,” Ensign or Liahona, May 2020, 84–87.
I believe the earth was created for families as taught throughout scripture (insert reference here) and as found in The Family: A Proclamation to the World. The family is sacred. Marriage is sacred. Many share different beliefs, but The Savior’s love is infinite and eternal (see D. Todd Christofferson) just as the family can be and is meant to be (insert scripture reference here). However, we all have our own agency (reference) and we must decide for ourselves the path we will follow. In the end, “Decisions determine destiny” (Thomas S. Monson).