I think we will always be back to this. Any Denomination or teaching that seeks to eradicate the Jews from Christianity is Satanic. If we ignore those, because the followers of such things will not be rebuked and be satisfied with that, we don't have to come back to certain aspects of the discussion as pertains to Gods eternal law.
As you observed, Jesus said He had other sheep who were not of "this fold", and He must bring them in also. So that there is one flock and one shepherd.
Another consideration concerning those Satanic doctrines. When they teach the laws of God are no longer applicable, they're teaching what can be recalled as, easy believerism. And also, hedonistic, carnal, faith practiced, because that teaching means also that sin is no longer an issue for those type believers. They can do whatever they like, because sin does not exist where there is no law.
The conflicting argument of that which is either Doctrine dedicated to anti-Judaism/Jewish or worse, antisemitism, often cites Saul as supporting the doctrine. Nothing could be further from truth.(*Saul/Paul) is my addition to the sentence below.
Benson Commentary
Romans 3:29-31. Is he the God of the Jews only? — He (*Saul/Paul) argues from the absurdity of such a supposition. Can it be imagined that a God of infinite love and mercy should limit and confine his favours to the little perverse people of the Jews, leaving all the rest of mankind in an eternally desperate condition? That would by no means agree with the idea we have of the divine goodness, for his tender mercies are over all his works. He is the God of the Gentiles also — And therefore hath established a way of justification, equally open to the Gentiles as to the Jews. Seeing it is one God — The same eternal and unchangeable Jehovah, that will justify the circumcision — The Jews, by faith; and the uncircumcision — The Gentiles, through the same faith — As if he had said, The way of justification is the same to both, whatever difference men may make in their expressions about it. He shows mercy to both, and by the very same means. Macknight thinks the expression, δια πιστεως, through faith, in the latter clause, is an ellipsis, for through the law of faith, mentioned
Romans 3:27, (where see the note,) and signifies the method of salvation by faith, established in the new covenant, called a law for the reasons there given. “By this law of faith the Gentiles are to be justified. For though they have not the doctrines of revelation, as the objects of their faith, they may believe the doctrines of natural religion, (
Hebrews 11:5,) and live agreeably to them: in which case their faith will be counted to them for righteousness, equally as the faith of those who enjoy revelation.” The same learned writer supposes, that in the expression, seeing there is one God, the apostle alludes to
Zechariah 14:8, where the prophet foretels the progress of the gospel, under the image of living waters going out from Jerusalem, and then adds,
Romans 3:9, And the Lord shall be king over all the earth, and in that day there shall be one Lord, and his name one; to show, that under the gospel dispensation, all nations shall be regarded by God as his people, that he will be acknowledged and worshipped by all nations, and that in the affair of their justification and salvation, he will observe one rule. Do we then — While we maintain this method of justification and salvation, make void the law — Set it aside, or render it useless, as καταργουμεν properly signifies; through faith — By teaching that justification is by faith, and that it is free for the Gentiles, as well as the Jews, in that way? God forbid — That we should ever insinuate such a design, or entertain such a thought; yea, we establish the law — On a firmer foundation than ever, and place it in a juster and more beautiful point of light: for we show that its honour is displayed in the atonement, as well as in the obedience of Christ; and we make it of everlasting use, for attesting the truth, and illustrating the necessity of the gospel, as well as for directing the lives of men, when they profess to have received it. In other words, we establish the authority, the purity, and the end of it; by defending that which the law attests, by pointing out Christ the end of it, and by showing how the moral part of it may be fulfilled in its purity. For through the influence of a faith that worketh by love, being enabled to love God, his children, and all mankind in sincerity and truth, we are brought to serve him without slavish fear, in holiness and righteousness before him, and to walk in his ordinances and moral commandments blameless. So that the righteousness of the law is fulfilled in us, while we walk, not after the flesh, but after the Spirit; love to God and man, productive of such fruits, being accounted by God the fulfilling of the law,
Romans 13:8-10;
Galatians 5:14;
James 2:8.
Thus also that more ancient and universal law, which God has written on men’s hearts, and which we have termed the law of nature, is established in the strongest manner in and by the gospel. For every one that makes the moral law of Moses the rule of his conduct, will also observe the precepts of this, as included therein.