1 Nephi 15:3 - 15:7

1 Nephi 15:3 For he truly spake many great things unto them, which were hard to be understood, save a man should inquire of the Lord; and they being hard in their hearts, therefore they did not look unto the Lord as they ought.

In addition, they would have a better feeling about the dream if they knew that it was for their benefit not for their condemnation if they would repent. Also if they would ask of God in prayer, they would know what the dream meant to them. But they were relying on their own wisdom and could not make a lot of sense of what their father had told them.

1 Nephi 15:4 And now I, Nephi, was grieved because of the hardness of their hearts, and also, because of the things which I had seen, and knew they must unavoidably come to pass because of the great wickedness of the children of men.

Nephi reaction is of grief. He had just had a wonderful experience when he had asked about the dream and knew that anyone could have the same and all that was required was to ask. But his brothers were too hard in their hearts to do that. They probably thought prayer was unmanly. Nephi was concerned because he saw what was to happen to both his and his brothers descendents.

1 Nephi 15:5 And it came to pass that I was overcome because of my afflictions, for I considered that mine afflictions were great above all, because of the destruction of my people, for I had beheld their fall.

Seeing this condition with his brothers and knowing what it will lead to in the future and it effects on his descendents, Nephi becomes sick of heart. It weighs him down so much that he has to get away from them for a while to recover his emotions so as to talk to them about their questions. Nephi has seen the death by brutal warfare and wickedness. He knows it got its start with the attitudes of his older brothers against him and their father. It would be hard to deal with this situation knowing the outcome and the almost uselessness of talking to these two older brothers who have their minds already made up and Nephi knows they will not change.

1 Nephi 15:6 And it came to pass that after I had received strength I spake unto my brethren, desiring to know of them the cause of their disputations.

After recovering his emotions, Nephi asked what they are wondering about.

1 Nephi 15:7 And they said: Behold, we cannot understand the words which our father hath spoken concerning the natural branches of the olive tree, and also concerning the Gentiles.

The boys say that they do not get the connection between the natural branches of the olive tree and the Gentiles. Lehi spoke about this in chapter 10:12-14. I guess they could not see why the Gentiles would have any roll in bring the Jews back to Palestine in the future as Lehi described.