Will Israel remain spiritually blind forever?
No. Israel's spiritual blindness is temporary, not permanent. Although the nation has been blinded because of rejecting the Messiah, Scripture indicates one day the nation will still see the truth of their Messiah. As Isaiah says, a nation will be born in a day. Individual Jews can be saved today by believing.
Les explains that Elimas the sorcerer is a prophetic picture of the nation as a whole: they would oppose the gospel at every turn. They were spiritually blinded, but not forever, because one day the nation of Israel is still going to see the truth of their Messiah. As Isaiah says, a nation will be born in a day. Yet a Jew can be saved today, the same as any Gentile, if he can open his eyes and spiritual heart and believe it. For the most part, the nation has been blinded because of their rejection of the Messiah.
Who hath heard such a thing? who hath seen such things? Shall the earth be made to bring forth in one day? or shall a nation be born at once? for as soon as Zion travailed, she brought forth her children.