Yes, it is. The Jews have no choice in their belief-structure. God has made the Jews blind to Jesus' Truth (that He is the Messiah, and one true Son of God), and will allow Israel to believe only when it suits His Divine Plan to do so.
For God alone is in control of all good works, and the Author of all good things.
You might have as easily asked, "How did they know over 2,000 years ago that, in the Year of Our Lord 1012, the tiny Nation-State of Israel would not only still be aroundsurrounded on all sides by her enemies, no lessbut that Israel would "...hang like a millstone (heavy burden) around the neck of the world..."
"tis far more 'twixt Heaven and Earth, Horatio..."
;^|
Not saying I'm agreeing, mind you: I'm saying I'm thinking.