President Packer spoke about the Holy Ghost in the following October 1994 General Conference. I will read some part of his talk:
[Child bears testimony of the Holy Ghost]
Following baptism, in the ordinance of confirmation, you received, or will receive, the gift of the Holy Ghost.
While the Holy Ghost may inspire all mankind, the gift carries the right to have it as a “constant companion” (see D&C 121:46). It is “by the power of the Holy Ghost [that you] may know the truth of all things” (Moro. 10:5).
The Holy Ghost speaks with a voice that you feel more than you hear. It is described as a “still small voice” (see D&C 85:6). And while we speak of “listening” to the whisperings of the Spirit, most often one describes a spiritual prompting by saying, “I had a feeling …”
The scriptures are full of such expressions as “The veil was taken from our minds, and the eyes of our understanding were opened” (D&C 110:1), “I will tell you in your mind and in your heart” (D&C 8:2), and “Speak the thoughts that I shall put into your hearts” (D&C 100:5).
The prophet Enos said, “While I was thus struggling in the spirit, behold, the voice of the Lord came into my mind” (Enos 1:10). Enos then related what the Lord put into his mind.
The voice of the Spirit speaks gently, prompting you what to do or what to say, or it may caution or warn you. Ignore or disobey these promptings, and the Spirit will leave you. It is your choice—your agency.
The Savior said: “If ye love me, keep my commandments.
“And I will pray the Father, and he shall give you another Comforter, that he may abide [stay] with you for ever;
“Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you.” (John 14:15–17.)
(SOURCE: Boyd K. Packer, “The Gift of the Holy Ghost,” Friend, Jul 1995, inside front cover)