Romans 11:7-8 : What then? That which Israel seeketh for, that he obtained not; but the election obtained it, and the rest were hardened: according as it is written, God gave them a spirit of stupor, eyes that they should not see, and ears that they should not hear, unto this very day. Here it seems that Paul begins to sum up his argument concerning Israel and God's dealings with them. The most of them had sought righteousness by the works of the law; but righteousness by works of law required perfect obedience to that law, and all had at some time sinned against that law. The law does not forgive; it cannot make the guilty righteous, or, what is the same, cannot justify the guilty. A remnant had sought forgiveness through Christ; these were the election, or the elect, that obtained righteousness. "The rest were hardened" that is, dulled or blinded.
Their will was hardened; their understanding was dulled. They, and not God, brought that condition upon themselves. Compare Matthew 13:14-15 : "And unto them is fulfilled the prophecy of Isaiah, which saith, By hearing ye shall hear, and shall in no wise understand; and seeing ye shall see, and shall in no wise perceive: for this people's heart is waxed gross, and their ears are dull of hearing, and their eyes they have closed lest haply they should perceive with their eyes, and hear with their ears, and understand with their heart, and should turn again, and I should heal them."
Jesus did not offer the Jews what they wanted they, therefore, turned a deaf ear to his teaching. They did not see in him anything they desired. They would not hear and they would not see, and, therefore, did not understand and that condition prevailed to the time Paul wrote the Roman letter, arid has not improved even until now. In verse 8 Paul makes a free translation of Deu 29:4 and Isaiah 29:10.