try starting with Galatians 1 and read through 4 - paul takes the physical to allegorize the spiritual.
he ends up saying that unbelieving jews of his day were like hagar - slaves to the Law (first covenant).
he says that Christians, like Isaac, were (and are) persecuted by the unbelieving jews.
ppl don't realize how severe and serious the persecution at the hands of the jews was (as well as at the hands of the gentiles).
Gal 3
Sons Through Faith in Christ
26You are all sons of God through faith in Christ Jesus. 27For all of you who were baptized into Christ have clothed yourselves with Christ. 28There is neither Jew nor Greek, slave nor free, male nor female, for you are all one in Christ Jesus. 29And if you belong to Christ, then you are Abraham’s seed and heirs according to the promise.
Galatians 4
Galatians 4 BSB < read all of it. you will see it.