Replacement theology? Yes or No.

[Revelation1v8]

Abraham is also the father of many nations, not only through Ishmael and the children of Keturah, but spiritually through the gospel of Christ.

The seed of Ishmael was not called to inherit the land.

According to biblical texts, the covenant promises and the specific inheritance of the Promised Land were established exclusively through Isaac, not Ishmael. God explicitly rejected Abraham’s plea to bless Ishmael with the covenant, stating, "But my covenant will I establish with Isaac" (Genesis 17:21). While Ishmael was blessed with fruitfulness and became a great nation, he was bypassed as the heir of the Abrahamic covenant, which designates the land of Canaan as an everlasting possession for the descendants of Abraham, Isaac, and Jacob.

Biblical Narrative: Ishmael received other blessings and lands outside the specific covenant of Canaan, such as the wilderness of Paran, and was circumcised but excluded from the primary covenant line.

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[Revelation1v8]

These all inherit the new heavens and new earth together with Abraham Isaac and Jacob.
It is the same inheritance.

Yes, anyone can inherit the new heaven and new earth who come to God/Jesus through faith. That doesn't mean that any of us were intended to inherit the promised land, although we will inherit the rest of the earth during the 1,000 years mentioned in Revelation 20 and throughout the Old Testament. Then we will see the new heaven and earth come into existence and none of it will matter.

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