Application to Israel: The Lord points out the tremendous irony of the Chosen People. They have received favors and prophecies, but have not understood them. They have had the witness of the Lord's power, and not recognized it. The Lord has shown unto them "hidden things" and they were not able to recognize them for what they were.
Application to Nephi's audience: Laman and Lemuel were certainly directly under this condemnation, for no less than an angel had been sent to them, but they still could not find a way to "declare" the things of God - but rather they continually rationalized their position, and continually relapsed to old ways.