Mormon 8

As Moroni concludes the record of his father, Mormon, he writes to both the believers and unbelievers including that state of the world (which is obvious today) in the days following the coming of the Book of Mormon to an overall summary of the plan of salvation or happiness.  In doing so, he speaks of all the prophets and saints that had preceeded him writing -

"Search the prophecies of Isaiah. Behold, I cannot write them. Yea, behold I say unto you, that those saints who have gone before me, who have possessed this land, shall cry, yea, even from the dust will they cry unto the Lord; and as the Lord liveth he will remember the covenant which he hath made with them."  (Book of Mormon | Mormon 8:23)

For -

"...he knoweth their prayers, that they were in behalf of their brethren..."  (Book of Mormon | Mormon 8:24)

And with some understanding concerning the prophecies and prayers of these saints, Moroni tells us  -

"...behold, their prayers were also in behalf of him that the Lord should suffer to bring these things forth."
(Book of Mormon | Mormon 8:25)

The ancient prophets were all aware of the Prophet Joseph Smith.  They all looked forward to the day that he would be called to bring forth this record for -

"...no one need say they shall not come, for they surely shall, for the Lord hath spoken it; for out of the earth shall they come, by the hand of the Lord, and none can stay it; and it shall come in a day when it shall be said that miracles are done away; and it shall come even as if one should speak from the dead.  (Book of Mormon | Mormon 8:26)

In conclusion, Moroni again speaks of the prayers of the prophets and saints -

"...these things which we have desired concerning our brethren, yea, even their restoration to the knowledge of Christ, are according to the prayers of all the saints who have dwelt in the land.
37  And may the Lord Jesus Christ grant that their prayers may be answered according to their faith; and may God the Father remember the covenant which he hath made with the house of Israel; and may he bless them forever, through faith on the name of Jesus Christ..." (Book of Mormon | Mormon 9:36 - 37)