Moroni prophesied of the day when the Book of Mormon would come forth. He said it would be a day when it shall be said that miracles are done away (Mormon 8:26). He explains the falseness of this doctrine later when he writes:
'And now, O all ye that have imagined up unto yourselves a god who can do no miracles, I would ask of you, have all these things passed, of which I have spoken? Has the end come yet? Behold I say unto you, Nay; and God has not ceased to be a God of miracles.
Behold, are not the things that God hath wrought marvelous in our eyes? Yea, and who can comprehend the marvelous works of God?
Who shall say that it was not a miracle that by his word the heaven and the earth should be; and by the power of his word man was created of the dust of the earth; and by the power of his word have miracles been wrought?
And who shall say that Jesus Christ did not do many mighty miracles? And there were many mighty miracles wrought by the hands of the apostles.
And if there were miracles wrought then, why has God ceased to be a God of miracles and yet be an unchangeable Being? And behold, I say unto you he changeth not; if so he would cease to be God; and he ceaseth not to be God, and is a God of miracles.
And the reason why he ceaseth to do miracles among the children of men is because that they dwindle in unbelief, and depart from the right way, and know not the God in whom they should trust.' (Mormon 9:15-20)
"Because faith is wanting, the fruits are. No man since the world was had faith without having something along with it. The ancients quenched the violence of fire, escaped the edge of the sword, women received their dead, etc. By faith the worlds were made. A man who has none of the gifts has no faith; and he deceives himself, if he supposes he has. Faith has been wanting, not only among the heathen, but in professed Christendom also, so that tongues, healings, prophecy, and prophets and apostles, and all the gifts and blessings have been wanting." (Teachings of the Prophet Joseph Smith, p. 270)