The Book of Mormon has a scene where Samuel the Lamanite gives a prophecy of a dramatic sign to come the night before the birth of the Messiah. In five years, there will be a night when it stays bright as the sun sets, giving a sign of the Savior's birth. From Helaman 14 we read:
 And now it came to pass that Samuel, the Lamanite, did prophesy a great many more things which cannot be written.
 And behold, he said unto them: Behold, I give unto you a sign; for five years more cometh, and behold, then cometh the Son of God to redeem all those who shall believe on his name.
 And behold, this will I give unto you for a sign at the time of his coming; for behold, there shall be great lights in heaven, insomuch that in the night before he cometh there shall be no darkness, insomuch that it shall appear unto man as if it was day.
 Therefore, there shall be one day and a night and a day, as if it were one day and there were no night; and this shall be unto you for a sign; for ye shall know of the rising of the sun and also of its setting; therefore they shall know of a surety that there shall be two days and a night; nevertheless the night shall not be darkened; and it shall be the night before he is born.
 And behold, there shall a new star arise, such an one as ye never have beheld; and this also shall be a sign unto you.
 And behold this is not all, there shall be many signs and wonders in heaven.
 And it shall come to pass that ye shall all be amazed, and wonder, insomuch that ye shall fall to the earth.
Over the next five years, many other less dramatic signs have come to pass, which are easily handled by the critics with arguments similar to what we often hear today in discussions, say, of Book of Mormon evidence, as we read in Helaman 16:
 Some things they may have guessed right, among so many; but behold, we know that all these great and marvelous works cannot come to pass, of which has been spoken.Lucky guesses and logical fallacies, nothing worthy of any interest.
 And they began to reason and to contend among themselves, saying:
 That it is not reasonable that such a being as a Christ shall come; if so, and he be the Son of God, the Father of heaven and of earth, as it has been spoken, why will he not show himself unto us as well as unto them who shall be at Jerusalem?
 Yea, why will he not show himself in this land as well as in the land of Jerusalem?
 But behold, we know that this is a wicked tradition, which has been handed down unto us by our fathers, to cause us that we should believe in some great and marvelous thing which should come to pass, but not among us, but in a land which is far distant, a land which we know not; therefore they can keep us in ignorance, for we cannot witness with our own eyes that they are true.
 And they will, by the cunning and the mysterious arts of the evil one, work some great mystery which we cannot understand, which will keep us down to be servants to their words, and also servants unto them, for we depend upon them to teach us the word; and thus will they keep us in ignorance if we will yield ourselves unto them, all the days of our lives.
 And many more things did the people imagine up in their hearts, which were foolish and vain; and they were much disturbed, for Satan did stir them up to do iniquity continually; yea, he did go about spreading rumors and contentions upon all the face of the land, that he might harden the hearts of the people against that which was good and against that which should come.
 And notwithstanding the signs and the wonders which were wrought among the people of the Lord, and the many miracles which they did, Satan did get great hold upon the hearts of the people upon all the face of the land.
The anti-Messiah sentiment in Nephite society had become powerful among the movers and shakers in their society, so powerful that a plan was even concocted to provide a final solution to manage the divisive, retrograde believers who were such a roadblock to progress. The opportunity came with the apparent failure of Samuel's prophecy and the huge momentum this gave opponents of the Church, as we read in 3 Nephi 1:
 And it came to pass that in the commencement of the ninety and second year, behold, the prophecies of the prophets began to be fulfilled more fully; for there began to be greater signs and greater miracles wrought among the people.
 But there were some who began to say that the time was past for the words to be fulfilled, which were spoken by Samuel, the Lamanite.
 And they began to rejoice over their brethren, saying: Behold the time is past, and the words of Samuel are not fulfilled; therefore, your joy and your faith concerning this thing hath been vain.
 And it came to pass that they did make a great uproar throughout the land; and the people who believed began to be very sorrowful, lest by any means those things which had been spoken might not come to pass.
This was a difficult time for the believers, for the argument against their faith was strong enough, in spite of other prophecies and signs having been fulfilled, that they began to be very sorrowful, wondering if the sign had actually failed. I presume that some turned from their faith at this point, and that it was the "true believers" who held on and waited, as we read next, and as we read of the audacious and intolerant deadline imposed by those in power:
 But behold, they did watch steadfastly for that day and that night and that day which should be as one day as if there were no night, that they might know that their faith had not been vain.The prophecy would be fulfilled right before the deadline given, but it does not appear that the believers were dealing with the arguments against them by saying, "Hold on, guys. Samuel said five years, and it's only been 4.9. Nothing is supposed to happen yet." No, they were worried and fearful.
 Now it came to pass that there was a day set apart by the unbelievers, that all those who believed in those traditions should be put to death except the sign should come to pass, which had been given by Samuel the prophet.
Going back to Samuel's prophecy, he doesn't exactly say that the sign would come in five years. He says five years will pass, "and then" the sign will come. So it's after five years. Five years and a month? Six months? I'm not sure. But I suspect that the prophecy became widely understood as a sign to come in five years. After five years had passed, the critics could rejoice and the believers began to fear. There's a subtle point in Helaman 14:2 that I didn't notice until yesterday, right before I gave a talk in sacrament meeting and was inspired by the Primary children having just sung about Samuel the Lamanite. As I was wondering about that prophecy and the misunderstanding, that's when I noticed Helaman 14:2's wording, and decided to change my talk to emphasize that story. I asked people if they would be able to hold onto their faith in that day, with such influential arguments and popular sentiment against it? And can they hold onto it today, when there is still much we don't understand, in spite of many signs, miracles, and blessings we have received? That's another story. Here's what happens with the story in Third Nephi 1:
 Now it came to pass that when Nephi, the son of Nephi, saw this wickedness of his people, his heart was exceedingly sorrowful.A wonderful story to ponder as we remember the birth of Christ long again in a manger in Bethlehem (part of the ancient "land of Jerusalem" per Alma 7:10 and the Dead Sea Scrolls and Amarna Letters, but that's another story, too.)
 And it came to pass that he went out and bowed himself down upon the earth, and cried mightily to his God in behalf of his people, yea, those who were about to be destroyed because of their faith in the tradition of their fathers.
 And it came to pass that he cried mightily unto the Lord, all that day; and behold, the voice of the Lord came unto him, saying:
 Lift up your head and be of good cheer; for behold, the time is at hand, and on this night shall the sign be given, and on the morrow come I into the world, to show unto the world that I will fulfill all that which I have caused to be spoken by the mouth of my holy prophets.
 Behold, I come unto my own, to fulfill all things which I have made known unto the children of men from the foundation of the world, and to do the will, both of the Father and of the Son -- of the Father because of me, and of the Son because of my flesh. And behold, the time is at hand, and this night shall the sign be given.
 And it came to pass that the words which came unto Nephi were fulfilled, according as they had been spoken; for behold, at the going down of the sun there was no darkness; and the people began to be astonished because there was no darkness when the night came.
 And there were many, who had not believed the words of the prophets, who fell to the earth and became as if they were dead, for they knew that the great plan of destruction which they had laid for those who believed in the words of the prophets had been frustrated; for the sign which had been given was already at hand.
 And they began to know that the Son of God must shortly appear; yea, in fine, all the people upon the face of the whole earth from the west to the east, both in the land north and in the land south, were so exceedingly astonished that they fell to the earth.
 For they knew that the prophets had testified of these things for many years, and that the sign which had been given was already at hand; and they began to fear because of their iniquity and their unbelief.
 And it came to pass that there was no darkness in all that night, but it was as light as though it was mid-day. And it came to pass that the sun did rise in the morning again, according to its proper order; and they knew that it was the day that the Lord should be born, because of the sign which had been given.