Oct 17- 3rd Nephi 25

Understanding the Spirit of Elijah was so incredibly important to our Heavenly Father that He commanded the Savior to teach the Nephites about it, and he commanded Moroni to teach Joseph Smith about it as an essential part of the restoration. Why is the Spirit of Elijah and the keys of the sealing power so essential to our exaltation? And how can we be a part of God's work of salvation?