'Inheritance' in the Bible

For if the inheritance [of what was promised] is based on [observing] the Law [as these false teachers claim], it is no longer based on a promise; however, God granted it to Abraham [as a gift] by virtue of His promise.

But the Scripture has imprisoned everyone [everything—the entire world] under sin, so that [the inheritance, the blessing of salvation] which was promised through faith in Jesus Christ might be given to those who believe [in Him and acknowledge Him as God’s precious Son].

But what does the Scripture say?“Cast out the bondwoman [Hagar] and her son [Ishmael],For never shall the son of the bondwoman be heir and share the inheritance with the son of the free woman.”