Israel's part in God's plan

“I do not want you to be ignorant of this mystery, brothers, so that you may not be conceited: Israel has experienced a hardening in part until the full number of the Gentiles has come in.” Romans 11:25
Paul presents several ‘mysteries’ in the epistles, including how Jews and Gentiles have equal standing before God in the church (Eph. 3:6), and here, how Israel is on the sidelines, but only for a time, while the ‘fullness of the Gentiles’ is being gathered.
A ‘mystery’ in this sense is something that was not revealed in the Old Testament, but is now revealed in the New. The promise of salvation to the Gentiles is not a mystery, because it was revealed (Gen. 18:18, Ps. 22:27, Ps. 67:2, Isa. 49:6, etc.). But to have equal standing with the Jews – now that has only been revealed in the days of the church.
Many people are indeed, as Paul says, ‘ignorant’ of Israel’s current status before God. Through the Jews’ corporate rejection of Jesus Christ as their Messiah, the door of salvation was opened to the Gentiles (see Acts 28:28). But this is not to say that Israel is finished, or that it has been replaced by the church – a popular heresy today. Once the church is complete, at the Rapture, God’s attention will once again be turned to Israel in the last days. There will be great repentance (Zech. 12:10) and revival. The reason Paul doesn’t want us to be ignorant is “so that you may not be conceited”. Isn’t it interesting how this sums up the attitude of many who say the church has replaced Israel and now receives all her blessings!