When will Israel's spiritual blindness be removed?
This will occur after the period of Israel's partial blindness, when God has finished His work with the Gentiles and takes us out of the way. Then the blindness is lifted from the Jew, and all Israel shall be saved, restoring the nation to its original promises and covenant position.
Les explains that God is still going to finish His program with Israel. In Romans 11, after establishing that God will yet come back and restore the nation to its original promises and covenant position, He gives a time frame. The mystery is that spiritual blindness, in part—not forever, but for a period of time—has happened to Israel until God has finished His work with the Gentiles. He takes us out of the way, and then the blindness will be lifted from the Jew. Verse 26 then declares, “and so all Israel shall be saved.” Israel's fall brought salvation to the Gentiles and riches to the world, but their fullness and great future still lie ahead.
For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.