The Holy Ghost is a member of the Godhead. He is "a personage of Spirit" (Doctrine and Covenants 130:22) without a body of flesh and bones; therefore, His influence can be everywhere at once. He loves us just as the Father and the Son love us. He testifies of the Father, the Son, and all truth. He also prepares us to return to live in the presence of God by purifying and sanctifying our hearts until we have no more desire to do evil.
The gift of the Holy Ghost is the privilege to receive continual guidance and inspiration from the Holy Ghost. This gift is given to people who have been baptized and confirmed as members of The Church of Jesus Christ of Latter-day Saints. The gift of the Holy Ghost is enjoyed by all who truly receive it.
The Holy Ghost may temporarily guide a person without the gift of the Holy Ghost (see Doctrine and Covenants 130:23). This guidance is a temporary experience unless the person is baptized and receives the laying on of hands for the gift of the Holy Ghost. A Roman soldier named Cornelius received inspiration from the Holy Ghost telling him that the gospel of Jesus Christ was true, but he did not receive the gift of the Holy Ghost until after he was baptized. (See Acts 10.) According to Joseph Smith, the Holy Ghost would have left Cornelius if he had not been baptized and received the gift of the Holy Ghost. (See Teachings of the Presidents of the Church: Joseph Smith, p 97.)
People today who are not members of the Church know by the power of the Holy Ghost that the Book of Mormon is true (see Moroni 10:4-5). If they do not receive the gift of the Holy Ghost, that initial testimony will leave them and they will not receive the continuing assurance that can comes to those who have the gift of the Holy Ghost.
After people are baptized, they are confirmed as members of The Church of Jesus Christ of Latter-day Saints and are given the gift of the Holy Ghost by the laying on of hands. Every worthy elder of the Church, when authorized, may give the gift of the Holy Ghost to another person. Each person is told to "receive the Holy Ghost." This means that the Holy Ghost will come to us with inspiration and guidance only when we are faithful and desire His help. We are worthy of help from the Holy Ghost when we keep the commandments of God and keep our thoughts and actions pure.
When the Holy Ghost "speaks" to us, it is usually referred to as a "still small voice" (see 1 Kings 19:9-12; Helaman 5:30; Doctrine and Covenants 85:6). President Boyd K. Packer explained, "The Holy Ghost speaks with a voice that you feel more than you hear…. While we speak of `listening' to the whispering of the Spirit, most often one describes a spiritual prompting by saying, `I had a feeling….' This voice of the Spirit speaks gently, prompting you what to do or what to say, or it may caution or warn you" (Ensign, Nov. 1994, 60).
The gift of the Holy Ghost is one of the greatest gifts Heavenly Father gives to His children. It is through the Holy Ghost that we may know that God lives, that Jesus is the Christ, that the Book of Mormon is true, that God's Church has been restored to the earth, that Joseph Smith is a true prophet of God, and that there is a living prophet on earth today.
The Holy Ghost shows us all things that we must do (see 2 Nephi 32:5). The Holy Ghost sanctifies us to prepare us to live in God's presence. The Holy Ghost also brings other gifts to us. The gift of the Holy Ghost can also bring peace to our hearts and understanding of the things of God to our minds (see 1 Corinthians 2:9-12). I have received the Holy Ghost many times in my life. I am very grateful for the gift of the Holy Ghost. I love to feel the peace that He always brings, and I know that He love us.