What then? Israel failed to obtain what it was seeking. The elect obtained it, but the rest were hardened,  as it is written, “God gave them a spirit of stupor, eyes that would not see and ears that would not hear, down to this very day.” (ESV)
The Jews of the Apostle Paul's day would have surely made a claim that they were pursuing God. Isn't it interesting that those who put Jesus to death on a cross also would have made the claim that they were pursuing God. They accused Jesus himself of blasphemy. One who does not care about God would not care about blasphemy.
It is a tragic thing when those who are sincere also happen to be sincerely wrong. That was the case for the Jews of Paul's day. He says here in verse 7 that Israel failed to obtain what it was seeking. It was seeking righteousness, but had to settle for self-righteousness, not the righteousness which is by faith that comes through belief in Jesus Christ.
Who did obtain what the Jews were seeking? The elect. These were those who God had called unto himself. Those whom God called he also moved in their hearts by the Holy Spirit to draw them to faith. The elect of God did not try to depend on their works as the "hardened Jews" did. This is to say that some Jews believed and some did not.
In verse 8 Paul refers to Old Testament references where God hardened the hearts of his rebellious people. The fact is that God did not harden any hearts that were not also willing to be hardened. Sadly, there were people who would not yield to God's sovereign plan for their lives. They may have been seeking. They may have even been sincere. Sincerely wrong.
Be very careful that you are not just sincere. Be sure that you are following the truth of God's Word. Place your faith in the work of Jesus Christ, not in your own works. Be sincere. Do not be sincerely wrong.