Related resources...

Summary on the Attributes of God
Spurgeon on the Attributes of God

Israel of God - Is God "Finished" with Israel in His prophetic plan?

Off Site - Table Comparing/contrasting Israel & Church
Off Site - Does the Church Fulfill Israel's Program? - John Walvoord
The Jewish People, Jesus Christ and World History - S Lewis Johnson

Are you confused about God's plan for Israel? Then I highly recommend Tony Garland's 12 Hour Course on Romans 9-11 in which he addresses in depth the question of  What Will Happen to Israel?  (click) or see the individual lectures below)

Romans 9:1-5 Paul's Sorrow Concerning Israel
Romans 9:6-13 Children of the Promise
Romans 9:14-24 The Potter and the Clay
Romans 9:25-33 A Remnant Will be Saved
Romans 10:1-13 The Righteousness of God
Romans 10:14-21 Has Israel Not Heard?
Romans 11:1-6  God Has Not Cast Away The Jews
Romans 11:7-15 Life from the Dead
Romans 11:16-24 Two Olive Trees
Romans 11:25-36 The Salvation of Israel

Note that when you click the preceding links, each link will in turn give you several choices including an Mp3 message and brief transcript notes. The Mp3's are long (avg 70+ min) but are in depth and thoroughly Scriptural with many quotations from the Old Testament, which is often much less well understood than the NT by many in the church today. Garland takes a literal approach to Scripture, and his love for the Jews and passion to see them saved comes through very clearly in these 12 hours of teaching! Take your home Bible Study group through this series if you dare. Take notes on the tapes as the transcripts are a very abbreviated version of the audio messages. This course is highly recommended for all who love Israel! I think you will agree that Tony Garland, despite coming to faith after age 30 as an engineer, clearly has been given a special anointing by God to promulgate the truth concerning Israel and God's glorious future plan for the Jews. Garland has also produced more than 20 hours of superb audio teaching in his verse by verse commentary on the Revelation (in depth transcripts also available) which will unravel (in a way you did not think was possible considering the plethora of divergent interpretations) God's final message of the triumph and return of the our Lord Jesus Christ as the King of kings and Lord of lords! Maranatha!

YOU WILL SAY THEN: ereis (2SFAI) oun:

Paul anticipated that in spite of this clear truth, some of his Gentile readers would continue to argue against him.

BRANCHES WERE BROKEN OFF SO THAT I MIGHT BE GRAFTED IN: exeklasthesan (3PAPI) kladoi hina ego egkentristho (1SAPS): (11,12,17,23,24)

The Bible Knowledge Commentary explains that

The apostle anticipated the rebuttal a Gentile believer might make: Branches were broken off so that I could be grafted in. Though that was not the real reason the branches were broken off, Paul accepted the statement for the sake of argument. Then he pointed out that the real reason the branches were broken off was Israel’s unbelief and that any Gentile as a grafted-in branch stands (cf. Ro 5:2) by faith. (Walvoord, J. F., Zuck, R. B., & Dallas Theological Seminary. The Bible Knowledge Commentary. Wheaton, IL: Victor Books)

Thomas Constable commenting on Ro 11:19-20 adds that...

That is true. But they were broken (pruned) off because of their unbelief (their lack of real faith), and you are established through faith [because you do believe]. So do not become proud and conceited, but rather stand in awe and be reverently afraid. (Amplified)

Yes, but remember--those branches, the Jews, were broken off because they didn't believe God, and you are there because you do believe. Don't think highly of yourself, but fear what could happen. (NLT)

Granted that Jews were rejected because of their unbelief, but nevertheless there was no personal merit in the Gentiles by which they became recipients of the divine favor. That favor was bestowed on the condition of their faith, and faith excludes boasting (Ro 3:27). Accordingly the real cause of their rejection is sufficient to correct a false inference.

DO NOT BE CONCEITED BUT (have an attitude of reverential awe) FEAR: me hupsela phronei (2SPAM) alla phobou (2SPPM): (18; 12:16; Psalms 138:6; Proverbs 28:26; Isaiah 2:11,17; Habakkuk 2:4; Zephaniah 3:11; Luke 18:14; 2 Corinthians 10:5; 2 Thessalonians 2:4; 2 Timothy 3:3-5; James 4:6; 1 Peter 5:5,6; Revelation 3:17; Revelation 18:7) (Proverbs 28:14; Isaiah 66:2; 1 Corinthians 10:12; Philippians 2:12; Hebrews 4:1; 1 Peter 1:17)

Stop thinking so high

Stop having a superiority complex, but be fearing (Wuest)

The situation does not call for conceit but for a certain wholesome fear. (Phillips)

Conceited is two words in Greek - (5308) (hupselós) which means high or lofty. The second word is (5426) (phroneo) which means to think, to have a mindset, to be minded. The activity represented by phroneo involves the will, affections, and conscience. The combination means to be high-minded, lofty in mind, proud or arrogant. The present imperative with the negative Greek word ("me" = conveys negation) calls for the reader to cease from an attitude that they are presently manifesting (i.e., spiritual arrogance toward the Jews).

Fear (5399) (phobeo from phobos = alarm or fright, fear, terror, reverence, respect, honor) means to cause to run away, to frighten, to terrify, to be alarmed. As used here phobeo conveys more the sense of to revere, to reverence or to be in awe of God. The present imperative calls for this to be one's lifestyle or habitual practice.

If Israel’s special calling and blessing from the Lord could not protect them from being broken off, then certainly the Gentiles’ lack of that calling and blessing cannot protect them from being broken off for their unbelief.

Therefore you would do well, Paul advises his Gentile readers, to have a righteous holy fear and to strongly resist any temptation to arrogance (Ro 11:18) and conceit (Ro 11:20). If God cut off apostate Israel because of her unbelief, how much more surely will He cut off an apostate church because of unbelief.

As alluded to in a previous comment, this is a warning the "Church" has failed to heed as manifest by the evolution of allegorical interpretation of Scripture by the early church fathers such as Origen so that by the time of Augustine this respected and influential teacher taught that Israel was replaced by the Church, in this case the Roman Catholic church. And so it went for the first 1000 years and thus Jews were often despised and hated and persecuted by the very ones who Paul is clearly stating should have known better. Probably few of these were truly saved but only pretending to be ''Christians'', although even such revered saints as Martin Luther in his later years published vitriolic diatribes against the Jews even calling for their tongues to be torn out if they did not convert! (See a sample link from a non-believing Jewish source)

Why did He not spare them? Why were they cut off? Their unbelief. And if God set aside Israel for their unbelief, He could do the same to Gentiles for their pride.

W E Vine comments that...