All from among Israel who continued in disobedience within the prior dispensation did not enter God's "rest" (Heb 3:18, 19), but ended in hell, i.e. rich man (Luke 16:22), same for the unbelieving Gentiles (remaining world). This excludes believers such as Abraham and others who were, "carried by the angels into Abraham's bosom" (paradise--heaven).
Those from among Israel and the Gentiles, who believe in Christ in the present dispensation, will be the Body of Christ. The primary subject in much confusion concerns those from among Israel who will be the last surviving generation of Israel. These are the ones concerning whom God said, "I will put My Spirit within you" (Eze 36:27), which is what He presently does for all believers (Phil 2:13). It’s my speculation those within this group will be separate in a position and authority than those of the Body, and I believe this is the intention of Romans 11:26, e.g. all among the last surviving Isrealites will be saved.
It’s also my speculation is that the Body will be eternally ruling (Mat 19:28; Luke 22:30) with Christ over these people (last of the Isrealites) who've inherited the new earth.