Here is the answer you gave and it is indeed a pitiful answer:
So here those under the law were Gentiles?:
"Therefore it is of faith, that it might be by grace; to the end the promise might be sure to all the seed; not to that only which is of the law, but to that also which is of the faith of Abraham; who is the father of us all" (Ro.4:16).
You are totally confused if you think that the words "which are of the law" are referring to Gentiles. And you accuse me of not being very astute.
It is you who is not very astute but worse you suffer from dementia. And you said nothing about what Peter, who lived under the law, said here:
"We believe it is through the grace of our Lord Jesus that we are saved, just as they are" (Acts 15:11).
Since Peter said that his salvation was on the principle of grace then it is obvious to anyone who will use his brains that "works" had nothing to do with his salvation.
Too many words to read. Make it simply and I may take a look?