ANSWER:
Your best weapon of choice is prayer, specifically spiritual warfare prayer. The Bible says that just like the veil was over Moses’ face, it is over the hearts and minds of the Jewish people so that they do not receive Christ, as their Messiah.
¹⁴ But their minds were blinded. To this day, the same veil remains uplifted in the reading of the Old Testament, because the veil is taken away in Christ. ¹⁵ But even to this day, when Moses is read, a veil lies on their heart (2 Corinthians 3:14–15).
You are dealing with demonic interference when sharing the Gospel with those who have already dismissed Jesus as the Messiah. Paul goes on to say:
³ But even if our gospel is veiled, it is veiled to those who are perishing, ⁴ whose minds the god of this age has blinded, who do not believe, lest the light of the gospel of the glory of Christ, who is the image of God, should shine on them
(2 Corinthians 4:3–4).
So, when praying for Jewish people, bind the demonic presence in their lives whose assignment is to keep them blinded to the truth of the Gospel. And pray for the truth of the Gospel to penetrate them.
The reason that Jewish people are not coming to Jesus in large numbers is that we are still in the Age of the Gentiles. By-and-large, when the Jewish nation rejected Jesus, the Gospel was taken to the Gentiles. In Romans 11, Paul talks about the wild olive branches (the Gentiles) now being grafted into the natural roots (the Jews). While this period of time is happening, the Jewish people are blinded to the Gospel. But the day will come when the Age of the Gentiles is complete, and the natural branches (the Jews) will be grafted back in. Then all those in Christ will be the true Israel of God, Jews and Gentiles alike.
²⁵ For I do not desire, brethren, that you should be ignorant of this mystery, lest you should be wise in your own opinion, that blindness in part has happened to Israel until the fullness of the Gentiles has come in. ²⁶ And so all of Israel will be saved … (Romans 11:25–26a).
I am not discouraging you from witnessing to your Jewish friends. They can be saved. The Bible says they are “blinded in part.” Jesus’ ministry was exclusive to the Jewish nation (Matthew 10:5-6, 15:24), however, there were a few Gentiles who received Him during that time.
For practical ways of ministering to Jewish people, let me connect you privately to a good friend of mine who is a Jewish Christian.
Many Blessings!