3 Nephi 12

After having taught the people in the Americas much of the words He taught in His mortal ministry, the Savior explains -

"...that when Jesus had ended these sayings he cast his eyes round about on the multitude, and said unto them: Behold, ye have heard the things which I taught before I ascended to my Father; therefore, whoso remembereth these sayings of mine and doeth them, him will I raise up at the last day." (Book of Mormon | 3 Nephi 15:1)

Suggesting that these teachings were essential for salvation for all people. But we are also taught by the Savior -

"...that in the mouth of two or three witnesses every word may be established." (New Testament | Matthew 18:16)

Which would also teach that much of the teachings and doctrine of the kingdom would be referenced in multiple books or records of scripture.

As much the same teachings that the Savior gave during His mortal ministry and re-taught in the Americas, I noticed something that I thought was significant. In Matthews record of the called beattitudes, the Savior taught -

"Blessed are the poor in spirit: for theirs is the kingdom of heaven.
4 Blessed are they that mourn: for they shall be comforted." (New Testament | Matthew 5:3 - 4)

In my mind, verse 4 suggests that any that mourn will be comforted. But in His teachings to the Americas, it is recorded -

"Yea, blessed are the poor in spirit who come unto me, for theirs is the kingdom of heaven.
4 And again, blessed are all they that mourn, for they shall be comforted." (Book of Mormon | 3 Nephi 12:3 - 4)

As I ponder this teaching, I note that the Savior teaches that those who are poor in spirit, or in words humble, "that come unto me" the kingdom shall be theirs. But then the Lord says "And again" which in my mind is another way of suggesting that those that comply with the previous verse "and" also mourn, it is those that shall be comforted. Not necessarily anyone that mourns.

Additional scripture or second witnesses always bring clarity and understanding.