JC - Chapter 39

Before the more righteous that had survived the great and terrible destruction in the Americas, the Savior -

"...knelt upon the earth; and behold he prayed unto the Father, and the things which he prayed cannot be written, and the multitude did bear record who heard him.

16 And after this manner do they bear record: The eye hath never seen, neither hath the ear heard, before, so great and marvelous things as we saw and heard Jesus speak unto the Father;

17 And no tongue can speak, neither can there be written by any man, neither can the hearts of men conceive so great and marvelous things as we both saw and heard Jesus speak; and no one can conceive of the joy which filled our souls at the time we heard him pray for us unto the Father."  (Book of Mormon | 3 Nephi 17:15 - 17)

And after praying, the Savior revealed -

"So great faith have I never seen among all the Jews; wherefore I could not show unto them so great miracles, because of their unbelief.

36 Verily I say unto you, there are none of them that have seen so great things as ye have seen; neither have they heard so great things as ye have heard."  (Book of Mormon | 3 Nephi 19:35 - 36)

Blessings and miracles are always a function of faith, not for a sign.