The tree in Romans 11 is not an earthly Israel.
That is not entirely correct, in that it denies Israel's part in the Tree. The Tree is the provision of God and the branches are the People of Israel:
Romans 11:16-18
King James Version (KJV)
16 For if the firstfruit be holy, the lump is also holy: and if the root be holy, so are the branches.
17 And if some of the branches be broken off, and thou, being a wild olive tree, wert grafted in among them, and with them partakest of the root and fatness of the olive tree;
18 Boast not against the branches. But if thou boast, thou bearest not the root, but the root thee.
The Tree is still there, and the Root is still there.
The Tree has not changed, it is the provision of God and Israel is specifically called the branches that were produced. It is National, not individual. That context is borne out through chs.9-11.
The tree is the Household of Faith.
No, the Tree is not the Household of faith, my friend.
You are suggesting that members of the Household of Faith were...
...cut out.
You need to give this a little more thought.
The root of this tree is Christ.
I would agree with that, for Christ is the provision of God in terms of redemption, which is a prominent issue in regards to Israel on a National basis.
And it is to National Israel that the Promises were made, and the Lord does not renege on His promises, but has always fulfilled every promise, and always will.
Why were the branches cut off? Unbelief.
That is correct.
So again, how do you confuse those that were cut out for unbelief, who we are told rejected Christ (He came unto His Own and His Own received Him not)...
...with the Household of Faith? Do you see the problem you have created for yourself?
Abraham was called being uncircumcised. He paid tithes to a Gentile priest, and received a blessing of the same.
And the relevance, my friend, is that the Law, though which Israel was brought into relationship with...does not nullify the Promises of God.
The Promises of God beginning in the Garden and continuing into the New Testament all work together in harmony to arrive at the same conclusion, which is a People of God set apart unto God.
Israel is a picture of what those promises would yield, and without Question they were the temporal People of God. Among those were those of faith. There has always been a remnant, but that did not disannul God's promises to National Israel.
And we are still waiting for those promises to be fulfilled in the Children of Promise.
Gentiles received the greatest miracles of Christ.
Sorry, no. You need to get this corrected soon, as it is completely contradictory to what Scripture teaches:
Galatians 3:27-29
King James Version (KJV)
27 For as many of you as have been baptized into Christ have put on Christ.
28 There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus.
29 And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise.
This is a fundamental blunder of great magnitude. It completely misses the heart of the Gospel of Jesus Christ.
The greatest faith He found on earth was in a Roman centurion.
This is contrasted to, yep, you guessed it...National Israel, who was in a state of destruction, just as all men were, when Christ came.
It is not a proof-text to replace Israel with Gentiles on a salvific and eternal basis.
The just shall live by faith.
That is true, but that is not relevant to the issue at hand, and it does not disannul the fact that the Just of both the Law as well as prior to the Law are equal on an eternal level. When God established the New Covenant the Just of those economies were then made perfect.
They did not receive the promises until Christ came.
And this is on a spiritual perspective which they were not privy to, which is actually the framework a-millennialism tries to build from.
You destroy it in thinking that Gentiles replace Israel, and deny many passages of Scripture that make it clear that the Just of both Jews and Gentiles have always been people of faith. That was true in the Old Testament, it is true in the New Testament.
Now, the Temple.
I would suggest getting the above error straightened out first.
It is clear you are not familiar with the purpose of the Law, so familiarizing yourself with some basic truths might help.
Galatians 3:23-25
King James Version (KJV)
23 But before faith came, we were kept under the law, shut up unto the faith which should afterwards be revealed.
24 Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith.
25 But after that faith is come, we are no longer under a schoolmaster.
Paul distinguishes between the faith of the Old Testament Saint and those under Law with the Faith of Jesus Christ.
But he also makes clear that the Law was meant to bring men to Christ. The writer of Hebrews speaks of the Hebrew Scriptures as the First Principles of the Doctrine of Christ, or put in another manner, the ABCs of the Knowledge of Christ.
Now that Christ has come...Faith has come.
And until you understand that truth you will confuse the temporal and the eternal, the physical with the spiritual. You will equate them and in so ding diminish that which God has accomplished in the lives of men in regards to Redemption.
What does the standing of an earthly temple signify?
The Writer calls it parable, a picture and shadow of the True, which was only fulfilled through Christ. That parable, picture, and shadow was incomplete, and did not produce life.
However, that parable was real, and brought temporal and temporary atonement, and was the prescribed Covenant meant to bring Israel, not the world, into relationship with God.
The true significance of the Tabernacle made with hands is that it was the place where Man could come into the presence of God. But just one man, the High Priest, who was a picture of our Great High Priest. And our Great High Priest did not enter into that Tabernacle, but into the true:
Hebrews 9
King James Version (KJV)
6 Now when these things were thus ordained, the priests went always into the first tabernacle, accomplishing the service of God.
7 But into the second went the high priest alone once every year, not without blood, which he offered for himself, and for the errors of the people:
8 The Holy Ghost this signifying, that the way into the holiest of all was not yet made manifest, while as the first tabernacle was yet standing:
9 Which was a figure for the time then present, in which were offered both gifts and sacrifices, that could not make him that did the service perfect, as pertaining to the conscience;
That earthly High Priest went into the Holy of Holies to make an offering for sin on the behalf of Israel, not the world.
But Christ...
13 For if the blood of bulls and of goats, and the ashes of an heifer sprinkling the unclean, sanctifieth to the purifying of the flesh:
14 How much more shall the blood of Christ, who through the eternal Spirit offered himself without spot to God, purge your conscience from dead works to serve the living God?
15 And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance.
...offered up a Sacrifice in a Tabernacle not made with hands for the purpose of redeeming the transgressions which had only been temporally and temporarily atoned for through the earthly, and He entered into...
24 For Christ is not entered into the holy places made with hands, which are the figures of the true; but into heaven itself, now to appear in the presence of God for us:
This is what that earthly Tabernacle, as well as the Temple...represented.
The presence of God was not possible for men prior to the Sacrifice of Christ, but He has opened up that way...
Hebrews 10:19-20
King James Version (KJV)
19 Having therefore, brethren, boldness to enter into the holiest by the blood of Jesus,
20 By a new and living way, which he hath consecrated for us, through the veil, that is to say, his flesh;
Hope that helps.
God bless.