In fact, the Torah (Devarim [Deuteronomy] 30.14) says, “that you may do it!” Paul says in his theology (Acts 15.10 “which neither we nor our fathers were able to keep.” Romans 7.14-24) you can not do it!!!! Either the Torah is correct (you may do it) or Paul is correct (which neither we nor our fathers were able to keep.) but both cannot be correct!
In another place, (Romans 11.26) he misquotes Yeshayahu (Isaiah) 59.20 which says, “A Redeemer shall come to Tzion, those of Ya’acov who repent from willful sin, the Words of HaShem.” (Romans 11.26 misquoting Isaiah 59.20 says, “There shall come out of Sion the Deliverer, And shall turn away ungodliness from Jacob:”
Paul’s Galatians 3.16 argument is a blunder in grammar because he ignores or is unfamiliar with the rules of interpretation: the word zeyrechah (your seed, B’rashith [Genesis] 13.15) is used (expressly qualified) in B’rashith (Genesis) 15.13-14 in the singular (yet 13.15 is further qualified by the phrase “im Yitzchaq” in 21.10) while expressed in the plural.
Both 13.15 and 15.13-14 your seed in the singular is qualified in the plural as them (a collective unity, that is, an afflicted NATION) and as they.
According to Rabbi Yishmael’s Rules of Interpretation, this is known as a gezeera shavah, which is also called hekesh, comparison!
That is, where one passuk [verse] is unclear, another verse or two verses containing similar words come to clarify the unclear passuk!) That is 13.15 is qualified by the statement of HaShem in B’rashith 15.5 and 15.13-14:
“And He took him outside, and He said, “Please look heavenward and count the stars, if you are able to count them.” And He said to him, “So will be your seed.””
13 “And He said unto Avram: ‘Know of a surety that thy seed shall be a stranger in a land that is not theirs, and shall serve them; and they shall afflict them four hundred years; 14 and also that nation, whom they shall serve, will I judge; and afterward shall they come out with great substance.”
Paul’s blunder is compounded by the fact that, the phrase, “im Yitzchaq” (with Isaac in B’rashith 21.10) is superfluous (See the Netsiv on 21.10 and Tehillim 105.9):
Tehillim 105.9 [The covenant] which He made with Abraham, and His oath unto Isaac; לְיִשְׂחָק
“Netsiv goes on to point out that Psalms 105, which is identical to chapter 16 in Chronicles I in all but one verse, foretells a better future, in which also Yitzchaq’s name will be altered. Referring to God’s covenant with the patriarchs, the ninth verse in this Tehillim (Psalm) differs from its correlate (Chronicles I, 16:16) in that the name Yitzchaq is spelled Yis’chaq in the phrase: “Ushevua-to leYitzchaq.” Says Netsiv, David foretold through divine inspiration that some day, the patriarch would be renamed to indicate the full joy that would replace the mockery.” Rabbi Naftali Zvi Yehuda Berlin of Volozhin, Ha’amek Davar: Commentary on the Pentateuch, New York: Friedman. <https://www.lookstein.org/professional-dev/and-sarah-laughed/>
In other words, the Torah does not need to say, “shall not inherit with my son, with Isaac;” as Sarah only produced one [singular] son, Yitzchaq [Isaac] through whom the inheritance of Eretz Yisrael [the Land of Israel] passes!
Wherefore she said unto Avraham: ‘Cast out this bondwoman and her son; for the son of this bondwoman shall not be heir with my son, even with Yitzchaq.’
Although, im Yitzchaq [with Isaac] is superfluous, it qualifies what Yishmael was guilty of so as to merit being disinherited:
The inheritance of the Land of Israel comes with joyous (faithful) laughter (of Avinu Avraham: “Avraham fell on his face and laughed” B’rashith 17.17); not the laughter of mockery (by Yishmael) of the Covenant of Circumcision!
Paul mockingly, calls the Covenant of Circumcision a “mutilation” (Philippians 3.2); but the Torah specifies who can partake of the Pesach (Passover) Korban (Sacrifice) (that is, the Torah specifies who can come into the Commonwealth of Israel; only those who are circumcised: “And when a stranger shall sojourn with thee, and will keep the Pesach to the L-RD, let all his males be circumcised, and then let him come near and keep it; and he shall be as one that is born in the land; but no uncircumcised person shall eat thereof.” “And One law shall be to him that is homeborn, and unto the stranger that sojourneth among you.'” “And if a stranger shall sojourn among you, and will keep the Pesach unto the L-RD; according to the ordinance of the Pesach, and according to the manner thereof, so shall he do: ye shall have one ordinance, both for the stranger, and for him that was born in the land.”
Because, Paul and the Jerusalem Council (Acts 15.1-29) stated that those non-Jews turning to HaShem did not need to be circumcised (that is, they stated there are two ordinances or standards for Pesach: one for the born Jew and one for those allegedly grafted into the Vine, or adopted as sons Romans 8.15, 11.17, Ephesians 3.6) they made a judgement contrary to the Torah, and counted as Avraham’s seed (heirs Galatians 3.29), non-Jews those HaShem explicitly excludes from the Covanant Promises made to Avraham and his descendants!
In conclusion, Paul tries to make an Arch-type-graphic (illustrative) argument that is not founded in the Torah!