Why did Israel, who pursued the law of righteousness, not attain it?
Israel did not attain the law of righteousness because they sought it not by faith. They pursued righteousness through the law, but they could not believe what God said. Scripture's absolute is that without faith it is impossible to please Him, while the Gentiles attained righteousness because they had faith.
Les explains that Israel's problem was unbelief. Israel followed after the law of righteousness but did not attain it because they sought it not by faith. They could not believe what God said, even though God's Word is a book of absolutes. Les stresses two absolutes in particular: without the shedding of blood there is no remission, and without faith it is impossible to please Him. By contrast, the Gentiles, who had not been following after righteousness, attained it because they had faith. They heard the Apostle Paul preaching and could believe it, but Israel shook their head. Les also applies this generally, saying we are not that much different today.
But Israel, which followed after the law of righteousness, hath not attained to the law of righteousness.
Wherefore? Because they sought it not by faith, but as it were by the works of the law. For they stumbled at that stumblingstone;