The passage doesn't seem too difficult at all. Paul is telling us Gentiles not to be ignorant or boastful, and that God is not finished with Israel.
The question of why some Christians support Israel is a complicated one. It incorporates politics as well as prophecy and instruction from the Lord.
Politically, they occupy a tiny spit of land. The ONLY true democracy in the region, surrounded by dictators, despots and vast hordes of muslims that want them liquidated. On that level alone, ALL of the West should support them.
Make no mistake, the vast majority of Jews today are either atheist/agnostic or extreme legalists. Many harbor ill will toward Christians.
We should never base our response to them based on the points above. Our response should be based on what the Lord would have us do.
In the OT we have "I will bless those that bless you and curse those that curse you". I don't see that as ended.
In the NT we see Jesus at the sheep and goat judgement basing His judgement on the nations and peoples of those nations on how they treated the Jews, especially during the Great Tribulation.
Notice the
DISTINCTION Jesus makes between the righteous Gentiles, and HIS BRETHREN. I believe He is talking about those Gentile Christians that helped the Jews in their persecution by the antichrist.
Matthew 25:
The Son of Man Will Judge the Nations
31 “When the Son of Man comes in His glory, and all the [
c]holy angels with Him, then He will sit on the throne of His glory. 32 All the nations will be gathered before Him, and He will separate them one from another, as a shepherd divides
his sheep from the goats. 33 And He will set the sheep on His right hand, but the goats on the left. 34 Then the King will say to those on His right hand, ‘Come, you blessed of My Father, inherit the kingdom prepared for you from the foundation of the world: 35 for I was hungry and you gave Me food; I was thirsty and you gave Me drink; I was a stranger and you took Me in; 36 I
was naked and you clothed Me; I was sick and you visited Me; I was in prison and you came to Me.’
37 “Then the righteous will answer Him, saying, ‘Lord, when did we see You hungry and feed
You, or thirsty and give
You drink? 38 When did we see You a stranger and take
You in, or naked and clothe
You? 39 Or when did we see You sick, or in prison, and come to You?’ 40 And the King will answer and say to them, ‘Assuredly, I say to you, inasmuch as you did
it to one of the least of these
My Brethren , you did
it to Me.’
41 “Then He will also say to those on the left hand, ‘Depart from Me, you cursed,into the everlasting fire prepared for the devil and his angels: 42 for I was hungry and you gave Me no food; I was thirsty and you gave Me no drink; 43 I was a stranger and you did not take Me in, naked and you did not clothe Me, sick and in prison and you did not visit Me.’
44 “Then they also will answer [
d]Him, saying, ‘Lord, when did we see You hungry or thirsty or a stranger or naked or sick or in prison, and did not minister to You?’45 Then He will answer them, saying, ‘Assuredly, I say to you, inasmuch as you did not do
it to one of the least of these, you did not do
it to Me.’ 46 And these will go away into everlasting punishment, but the righteous into eternal life.”