Joseph Smith
"The principle is as correct as the one that Jesus put forth in saying that he who seeketh a sign is an adulterous person; and that principle is eternal, undeviating, and firm as the pillars of heaven; for whenever you see a man seeking after a sign, you may set it down that he is an adulterous man." (Teachings of the Prophet Joseph Smith, p. 157)
George A. Smith
"I recollect a Campbellite preacher who came to Joseph Smith ... and said that he had come a considerable distance to be convinced of the truth. 'Why,' said he, 'Mr. Smith, I want to know the truth, and when I am convinced, I will spend all my talents and time defending and spreading the doctrines of your religion, and I will give you to understand that to convince me is equivalent to convincing all my society, amounting to several hundreds.' Well, Joseph commenced laying before him the coming forth of the work, and the first principles of the Gospel, when [the minister] exclaimed, 'O this is not the evidence I want, the evidence that I wish to have is a notable miracle; I want to see some powerful manifestation of the power of God, I want to see a notable miracle performed; and if you perform such a one, then I will believe with all my heart and soul, and will exert all my power and all my extensive influence to convince others; and if you will not perform a miracle of this kind, then I am your worst and bitterest enemy.' 'Well,' said Joseph, 'what will you have done? Will you be struck blind, or dumb? Will you be paralyzed, or will you have one hand withered? Take your choice, choose which you please, and in the name of the Lord Jesus Christ it shall be done.' 'That is not the kind of miracle I want,' said the preacher. 'Then, sir,' replied Joseph, 'I can perform none, I am not going to bring any trouble upon any body else, sir, to convince you.'" (Journal of Discourses, 1855, vol. 2, p. 326).