To answer your last two questions, Paul is trying to say that both Jews and Gentiles no longer have to be born into Judaism or follow the laws of Abraham to achieve salvation from God because Jesus Christ payed for all of the sins of humanity when he was crucified. Therefore, one only has to practice internal things like believe and have faith in Jesus Christ to be saved, whereas before one would have to practice external things like the law and be circumcised.There is no longer a need for the law because the commandments enabled humans to live a sinful life, as he stated in 3:20 "...through the law comes the knowledge of sin," however, through faith and the mercy of God, now more would be able to be saved if they became Christians. This is
