Application to Israel: Verses 7 and 8 combine to create a dual condemnation of Israel. In verse 7 Isaiah presents the idea that there are new prophecies, information given new and specifically so that Israel could not explain it away as the remnant of some older idea and therefore dismiss it. Verse 8 specifically condemns their inability to hear the word of the Lord, because "thine ear was not opened." Indeed, the Lord in his foreknowledge "new that thou wouldst deal very treacherously, as wast called a transgressor from the womb."
It is perhaps important to note that even under such scathing criticism, the Lord does not give up on his Chosen People, and continues to try to "open their ears."
Application to Nephi's audience: Once again the parallel between Laman and Lemuel and the Israel Isaiah is describing is tremendous. The Lord also foreknew the hardness of hearts of Laman, and Lemuel, and similarly did not shrink from attempts to "open their ears."