Ultimately, when Jesus returns and we are in the age of Resurrection, The Land will belong to The Seed and His children.
JLB
Hi, JLB. You wrote: "there can be no mistaking the reference to the natural descendants of Abraham."
LOL! Scriptures are misinterpreted and mistaken (and mistranslated) all the time. That is why there are about a zillion different denominations of Christian churches.
For example, your quotes of Genesis are from the "New" King James Version (NKJV), which tends to alter meanings found in the old 1611 King James Version that the 1909 Scofield Reference Bible uses (which I will label SKJV to avoid confusion.) In fact, the NKJV gives an entirely different meaning to the verses you quoted. The following are those verses from the SKJV:
"And I will give unto thee, and to thy seed after thee, the land wherein thou art a stranger, all the land of Canaan, for an everlasting possession; and I will be their God. And God said unto Abraham, Thou shalt keep my covenant therefore, thou, and thy seed after thee in their generations. This is my covenant, which ye shall keep, between me and you and thy seed after thee; Every man child among you shall be circumcised." - Genesis 17:8-10
"And I will make thy seed to multiply as the stars of heaven, and will give unto thy seed all these countries; and in thy seed shall all the nations of the earth be blessed; Because that Abraham obeyed my voice, and kept my charge, my commandments, my statutes, and my laws." - Genesis 26:4-5
Note the use of "seed" rather than "descendants". The SKJV matchs the context of the NT scripture by Paul in Galatians, which states the promises are fulfilled in Christ:
"Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ." - Galatians 3:16
Oddly, the NKJV altered the meaning of the Old Testament ref, but not the meaning of the New Testament ref, as follows:
"Now to Abraham and his Seed were the promises made. He does not say, "And to seeds," as of many, but as of one, "And to your Seed," who is Christ." - Galatians 3:16, NKJV
You wrote: "This Covenant and it's promises to the natural descendents of Abraham and Isaac, can not be annuled by the law of Moses, or the New Covenant, which is an extension of the Covenant with Abraham."
God can do as He pleases. It is His creation. Besides, Israel broke the covenant, not God, and Israel broke it in many ways: they polluted the temple, worshipped idols, broke the sabbath, violated marriage restrictions, and among other sins, did not run all of the resident nations off the "promised land" as God ordered them to do. That last violation, in itself, was reason enough for God to completely destroy Israel and give the land to others.
God gave these instructions to Israel regarding the current occupants of the "promised land:"
"Then ye shall drive out all the inhabitants of the land from before you, and destroy all their pictures, and destroy all their molten images, and quite pluck down all their high places: And ye shall dispossess the inhabitants of the land, and dwell therein: for I have given you the land to possess it." – Numbers 33:52-53
But God also warned Israel what would happen should they fail to drive out all the inhabitants of the land. He clearly states He would eventually do to Israel what He had planned to do unto the inhabitants (e.g., completely destroy them
“But if ye will not drive out the inhabitants of the land from before you; then it shall come to pass, that those which ye let remain of them shall be pricks in your eyes, and thorns in your sides, and shall vex you in the land wherein ye dwell. Moreover it shall come to pass, that I shall do unto you, as I thought to do unto them.” – Numbers 33:55-56
"And it shall be, if thou do at all forget the Lord thy God, and walk after other gods, and serve them, and worship them, I testify against you this day that ye shall surely perish. As the nations which the Lord destroyeth before your face, so shall ye perish; because ye would not be obedient unto the voice of the Lord your God." - Deuteronomy 8:19-20
That violation sealed Israel's fate. When considering all the ways Israel broke the covenants, including their total and complete pollution of the temple during our Lord's generation, and the fact that they persecuted and/or killed the prophets, apostles and saints, not to mention committing the worst crime in the history of the world--the murder of our Lord Jesus--is it any wonder Jesus called them "Children of the Devil" and Paul warned they were "contrary to all men." (John 8:44 and 1 Thessalonians 2:15)
Other bible translations of 1 Thess 2:15 declare the Jews to be "enemies of everyone," "hostile to everyone," "adversaries to all men," "working against all men," "foes of all men," "hostile to the entire human race," etc..
God ultimately destroyed all but a remnant in 70 A.D., and subsequently called many of that same remnant to serve Christ in laying the foundation of His Church, with Jesus being the chief cornerstone and, according to James in Acts 15:16, the conversion of the Cornelius the Gentile being the fulfillment of Amos 9:11, which reads:
"In that day will I raise up the tabernacle of David that is fallen, and close up the breaches thereof; and I will raise up his ruins, and I will build it as in the days of old" - Amos 9:11
Dan