Dallin H. Oaks
"(quoting Alma 32:15-19) There are two lessons here. First, those who acquire knowledge by means of signs have no occasion to develop faith. Without that spiritual development…and without the sustaining strength of faith, they are damned in their progress and remain vulnerable to transgression and to falling away. Second, those who acquire knowledge and then fall away are more cursed than those who, following the pathway of faith, have only come so far as to believe before they fall away.
"Thus, the showing of a sign can work to the condemnation of those who are brought to knowledge by that means. They miss the opportunity to develop faith, and they subject themselves to a more severe punishment for backsliding than those whose spiritual development is proceeding along the normal pathway of developing faith.
"There are other ‘condemnations’ to those who seek signs without first developing the faith God has required as a prerequisite.
"One condemnation is to be misled. God warned ancient Israel against following prophets who gave signs and wonders and then sought to lead them away to the worship of strange gods. (Deut. 13:1-3.) The Savior taught his apostles that in the last days ’there shall also arise false Christs, and false prophets, and shall show great signs and wonders, insomuch that, if possible, they shall deceive the very elect, who are the elect according to the covenant.’ (JST Matt. 24:23; also see Matt. 24:24; Mark 13:22.) The apostle Paul warned that the Savior would not come again ’until after there cometh a falling away, by the working of Satan with all power, and signs and lying wonders, and with all deceivableness of unrighteousness in them that perish.’ (JST 2 Thes. 2:9-10.)
"In the great revelation on signs, the Lord says, ’He that seeketh signs shall see signs, but not unto salvation.’ (D&C 63:7.) President Spencer W. Kimball explained: ’Certainly we should not be interested in signs. Signs are available and anyone, I believe, can have signs who wants them. I believe if one wants revelations enough to crave them beyond the rightness of it, that eventually he will get his revelations—but they may not come from God. I am sure that there can be many spectacular things performed, because the devil is very responsive. He is listening and he is eager to do it. And so he gives strange experiences.’
“…Manifestly, the performance of miracles and the appearance of signs and wonders are not evidences that those who do these things are servants of God or teachers of truth. In our day, God does not use miracles or signs as a way of teaching or convincing the unbeliever. As a result, we should not ask for signs for this purpose, and we should be deeply suspicious of the so-called spiritual evidences of those who do.” (The Lord’s Way, p. 86)
Elder Winslow Farr Smith
“It is a strange thing that many of our members are always looking for something absolutely extraordinary…Has it ever occurred to you that perfect knowledge is what the devil himself possesses? Has it ever occurred to you that many men, who fight against God and his kingdom, know beyond the question of a doubt that the Gospel is true. Has it ever occurred to you that in this fighting, the one thing that is lacking in their make-up is that very vital thing, faith in Almighty God? I beg of you to consider this question, weigh it very, very seriously. I have in mind a man right now, whom I met but a few weeks ago, who claims to have had revealed to him the Son of God himself, and yet that man lacks something in his make-up to hold him fast to the Church and to the gospel of Jesus Christ. Something has come between him and the testimony that he had, and instead of being a helper, a supporter of, and a fighter for, the doctrines of Christ, and the missionaries working in his field, he is a hindrance.” (Conference Report, Oct. 1919, p. 186, italics added)