3 Nephi 1:22

And it came to pass that from this time forth there began to be lyings sent forth among the people, by Satan, to harden their hearts, to the intent that they might not believe in those signs and wonders which they had seen; but notwithstanding these lyings and deceivings the more part of the people did believe, and were converted unto the Lord.

The sign of a night without darkness at the Savior's birth was dramatic enough to get people's attention so they would listen to the message of the gospel and the Messiah. Many were converted, or at least they joined the church. But conversion cannot be dependent on a sign. Just a few years later, this skin-deep conversion would slip away for many, and the people for the most part would return to apostasy. There are many ways to plant the seed of faith in people's hearts, but the seed must be nurtured and carefully cultivated, or it will not bear fruit.

3 Nephi 1:8

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 righteous believers did not need a sign to ignite their faith, but they needed the promised sign to confirm their faith. It is okay to ask for confirmation. That is not sign-seeking. It is like asking for a testimony of the Book of Mormon as you read it. It is not weakness to ask for validation of your faith as you exercise it. God wants us to ask, and he promises us marvelous answers.

Jacob 7:14

And I said unto him: What am I that I should tempt God to show unto thee a sign in the thing which thou knowest to be true? Yet thou wilt deny it, because thou art of the devil. Nevertheless, not my will be done; but if God shall smite thee, let that be a sign unto thee that he has power, both in heaven and in earth; and also, that Christ shall come. And thy will, O Lord, be done, and not mine.

Signs only confirm what we already believe. They do not convince or convert. We can always explain away a sign. Conversion comes through the heart and mind, not through the eye and ear.

Second Nephi 11:4

Behold, my soul delighteth in proving unto my people the truth of the coming of Christ; for, for this end hath the law of Moses been given; and all things which have been given of God from the beginning of the world, unto man, are the typifying of him.

Nephi teaches us here to look to all things as evidence of Christ and the plan of salvation that he has worked out through his atonement. Christ is the Light, the Rock, the Living Water. We must develop the eyes to see. The signs are all around us if we learn to look.