Personal revelation prevents deception because the Holy Ghost “speaketh of things as they really are, and of things as they really will be” (Jacob 4:13).
For they that are wise and have received the truth, and have taken the Holy Spirit for their guide, and have not been deceived—verily I say unto you, they shall not be hewn down and cast into the fire, but shall abide the day. (D&C 45:57.)
Again, the Holy Ghost speaks. It projects informational ideas, not feelings.
In the scriptures, we are given countless examples of revelation received. None of them indicate the reception of an emotion or feeling. God describes the mechanisms of revelation in plainness:
Verily I say unto you, he that is ordained of me and sent forth to preach the word of truth by the Comforter, in the Spirit of truth, doth he preach it by the Spirit of truth or some other way? And if it be by some other way it is not of God. And again, he that receiveth the word of truth, doth he receive it by the Spirit of truth or some other way? If it be some other way it is not of God. Therefore, why is it that ye cannot understand and know, that he that receiveth the word by the Spirit of truth receiveth it as it is preached by the Spirit of truth? Wherefore, he that preacheth and he that receiveth, understand one another, and both are edified and rejoice together. And that which doth not edify is not of God, and is darkness. That which is of God is light; and he that receiveth light, and continueth in God, receiveth more light; and that light groweth brighter and brighter until the perfect day. And again, verily I say unto you, and I say it that you may know the truth, that you may chase darkness from among you; (D&C 50:17-25.)
The Spirit of truth teaches not by issuing a feeling, but by giving the word of truth. “Therefore, whoso readeth it, let him understand, for the Spirit manifesteth truth;” (D&C 91:4.) It is truth and it is conveyed through words. Though revelatory ideas can come, as Joseph described, in a sudden rush, they are writable. You can translate those ideas into words.
The Lord does not say we should live by every feeling that proceeds from the mouth of God. He says:
For you shall live by every word that proceedeth forth from the mouth of God. For the word of the Lord is truth, and whatsoever is truth is light, and whatsoever is light is Spirit, even the Spirit of Jesus Christ. (D&C 84:44-45.)
Words come out of one's mouth, not feelings. Voices are heard, not felt.
Behold, that which you hear is as the voice of one crying in the wilderness—in the wilderness, because you cannot see him—my voice, because my voice is Spirit; my Spirit is truth; truth abideth and hath no end; and if it be in you it shall abound. (D&C 88:66.)
Some may quip that God's voice and the Holy Ghost are two separate things. However, the Book of Mormon prophets would disagree. Mormon wrote:
For immediately after I had learned these things of you I inquired of the Lord concerning the matter. And the word of the Lord came to me by the power of the Holy Ghost, saying: Listen [not feel] to the words of Christ, your Redeemer, your Lord and your God. Behold, I came into the world not to call the righteous but sinners to repentance; the whole need no physician, but they that are sick; wherefore, little children are whole, for they are not capable of committing sin; wherefore the curse of Adam is taken from them in me, that it hath no power over them; and the law of circumcision is done away in me. And after this manner did the Holy Ghost manifest the word of God unto me; wherefore, my beloved son, I know that it is solemn mockery before God, that ye should baptize little children. (Moroni 8:7-9.)
After what manner did the Holy Ghost manifest the word of God to Mormon? Through an audible voice. It would have been quite difficult to quote a textual sentence from God if all he was given was a feeling. When those purporting revelation produce no text, it is possible that, in reality, they merely experienced their own emotions and not a revelation from God.
Another popular misconception is to equate “still small voice” with a feeling, despite the fact that the phrase is not “still small feeling.” The phrase itself comes from the story of Elijah seeking God in a cave after much persecution. In response to his prayer, there was an earthquake,
And after the earthquake a fire; but the Lord was not in the fire: and after the fire a still small voice. And it was so, when Elijah heard it, that he wrapped his face in his mantle, and went out, and stood in the entering in of the cave. And, behold, there came a voice unto him, and said, What doest thou here, Elijah? (1 Kings 19:12-13.)
Even the example from which the phrase is lifted plainly describes the hearing of an actual voice. It communicated information, in this case causing him to leave the cave. In modern times, Joseph described the still small voiced in our canonized scriptures this way:
Yea, thus saith the still small voice, which whispereth through and pierceth all things, and often times it maketh my bones to quake while it maketh manifest, saying: And it shall come to pass that I, the Lord God, will send one mighty and strong, holding the scepter of power in his hand, clothed with light for a covering, whose mouth shall utter words, eternal words; while his bowels shall be a fountain of truth, to set in order the house of God, and to arrange by lot the inheritances of the saints whose names are found, and the names of their fathers, and of their children, enrolled in the book of the law of God; While that man, who was called of God and appointed, that putteth forth his hand to steady the ark of God, shall fall by the shaft of death, like as a tree that is smitten by the vivid shaft of lightning. And all they who are not found written in the book of remembrance shall find none inheritance in that day, but they shall be cut asunder, and their portion shall be appointed them among unbelievers, where are wailing and gnashing of teeth. These things I say not of myself; therefore, as the Lord speaketh, he will also fulfil. (D&C 85:6-10.)
Note that here Joseph attributes a paragraph of God's writeable word to the still small voice. To Joseph, the still small voice of the Holy Ghost was an actual voice that conveyed information. The detail here exceeds what an emotion or feeling could convey.