The Holy Ghost is the third member of the Godhead. He is a personage of spirit, without a body of flesh and bones. He is often referred to as the Spirit, the Holy Spirit, the Spirit of God, the Spirit of the Lord, or the Comforter.
ROLES OF THE HOLY GHOST
The Holy Ghost works in perfect unity with Heavenly Father and Jesus Christ, fulfilling several roles to help us live righteously and receive the blessings of the gospel.
He “witnesses of the Father and the Son” (2 Nephi 31:18) and reveals and teaches “the truth of all things” (Moroni 10:5). We can receive a sure testimony of Heavenly Father and Jesus Christ only by the power of the Holy Ghost. His communication to our spirit carries far more certainty than any communication we can receive through our natural senses.
As we strive to stay on the path that leads to eternal life, the Holy Ghost can guide us in our decisions and protect us from physical and spiritual danger.
He is the Comforter (John 14:26). As the soothing voice of a loving parent can quiet a crying child, the whisperings of the Spirit can calm our fears, hush the nagging worries of our life, and comfort us when we grieve. The Holy Ghost can fill us “with hope and perfect love” and “teach [us] the peaceable things of the kingdom” (Moroni 8:26; D&C 36:2).