Nephi finally gives us his description of how he felt after his great vision. One might suppose that he would be ecstatic (in all senses of that word) with the power of the vision he had seen. What he tells us is that he felt the weight of it. It is entirely possible that Nephi had mixed emotions ranging from the great joy of understanding better the role of the Savior to the pain of seeing the future history of his people. However those emotions might have been mixed, they turned firmly to the melancholy as he saw his brothers disputing the meaning of the vision. Nephi knew that the answers were available, for he had just received them - and more. With crystal clear spiritual acuity, Nephi sees the hardness of the hearts of his brethren, and sees clearly precisely how the future history he has seen will come to pass. For all of the miracles, it would be the hardness of hearts as he could see in his brothers which would bring it to pass. It had to hit him with tremendous impact, and is reflected in the tone of these verses.