In these three verses Nephi teaches a powerful lesson about the way the truth impacts those who are not in accord with its teachings. Nephi's brothers declare "Thou hast declared unto us hard things, more than we are able to bear" (verse 1), yet Nephi did not specifically condemn them. Somewhere in the description of the separation of the righteous and guilty they recognized themselves. Perhaps as the fathers of the progeny who would stray. In any case, Nephi made no accusations, but the guilt found the appropriate parties, and this time was sufficient to prick their hearts. They were not yet so far gone from the Spirit that it could not touch them.
Nephi recognizes their declaration of hard things for precisely what it was, the effect of the Spirit touching their hearts with the recognition of their need for repentance, to which Nephi exhorts them.