Paul, the apostle of Jesus to the Gentiles, was plagued all during his ministry by Judaizers much like you. He fought against them diligently with the power given him by God through the Holy Spirit.
Saul was a rabbi and Pharisee. He knows the Abraham and Mosaic Covenants were made between God and Abraham and his seed. Saul would not violate God's Word in any respect for if he did, he would be an outcast by the Jews for trying to teach Gentiles the Law of Moses given to the children of Israel nor would he ever seek to circumcise a Gentile. It would cause an uproar, and he would lose all credibility. But he was a very respected Jew whose obedience to the Law of Moses was unequaled.
17 And when we were come to Jerusalem, the brethren received us gladly.
18 And the day following Paul went in with us unto James; and all the elders were present.
19 And when he had saluted them, he declared particularly what things God had wrought among the Gentiles by his ministry.
20 And when they heard it, they glorified the Lord, and said unto him,
Thou seest, brother, how many thousands of Jews there are which believe; and they are all zealous of the law:
21
And they are informed of thee, that thou teachest all the Jews which are among the Gentiles to forsake Moses, saying that they ought not to circumcise their children, neither to walk after the customs.
22 What is it therefore? the multitude must needs come together: for they will hear that thou art come.
23 Do therefore this that we say to thee: We have four men which have
a vow on them;
24
Them take, and purify thyself with them, and be at charges with them, that they
may shave their heads: and
all may know that those things, whereof they were informed concerning thee, are nothing; but that thou thyself also walkest orderly, and keepest the law. Acts 21:17–24.
So, which is it? Is he obedient to the Law of Moses which covenant and Law is between the God of Israel and the children of Israel, or is he teaching non-Hebrew Gentiles to obey the Law and seeking to circumcise them in violation of the Law of Moses? Which is it?
We know of Samaritans who are descendants of the ten northern kingdom tribes and mixed heritage Hebrews called "Samaritan" by the Jews and not calling them Jews. But who was among the "remnant" that returned from Babylon at the leave of king Cyrus who conquered Judah and Benjamin in 586 BC and exiled them to Babylon? Where in the Bible are these two southern kingdom tribes mixed heritage Hebrews mentioned or named? The remnant of the two southern kingdom tribes (Judah and Benjamin) consisted of about 10% of ALL Jews alive at the time who remained in Gentile lands, a number that can be called the majority (90%) of ALL Jews alive at the time? Jesus interacted with Samaritans but what were the mixed heritage Hebrews of the two southern tribes called? Where are they mentioned in the Bible?
I submit that Saul never tried to teach non-Hebrew Gentiles the Law of Moses, nor did he ever seek to circumcise any in violation of the Law of Moses. Saul was apostle to mixed heritage Hebrews who no matter the dilution of their DNA was STILL seed of Abraham and heirs according to the PROMISE. These "lost" sheep grew up in Gentile lands heavily influenced by Greek culture and from 722 BC until Christ about 15-20 generations of Jews that were never circumcised were the "Gentiles" that the Jews wanted to circumcise after they became born-again which led to the Jerusalem Council. Now, if these Jewish Christians (born-again practicing Jews) were obedient to the Law of Moses as declared in Acts 21:20 and Judaizers wanted to circumcise these mixed heritage Hebrews who grew up outside the commonwealth of Israel and were "without Christ, being aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world: But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ" are the "Gentiles" so-called by the Jews because they were uncircumcised, lost in and under Gentile and Greek culture for generations until Christ but were born-again and remained the seed of Abraham and were the subject of the Jerusalem Council concerning circumcision of these half-Jew/Gentile Hebrews. James, Peter, Saul, and the other apostles and elders (including born-again priests of the Sanhedrin...)
7 And the word of God increased; and the number of the disciples multiplied in Jerusalem greatly; and a great company of the priests were obedient to the faith. Acts 6:7.....
would NEVER cause a real non-Hebrew Gentile to be circumcised nor would they give them four precepts of the Law of Moses to obey if they were non-Hebrew Gentiles. Pay attention:
19 Wherefore my sentence is, that we trouble not them, which [JEWS]
from among the Gentiles are turned to God:
20 But that we write unto them,
that they abstain from pollutions of idols,
and
from fornication,
and
from things strangled,
and
from blood.
21 For Moses of old time hath in every city them that preach him, being read in the synagogues every sabbath day. Acts 15:19–21.
IF they were real non-Hebrew Gentiles the Jewish Christians in Jerusalem would not enjoy the respect of the Jewish people only because they were as Jewish Christians STILL obedient to the Law of Moses, such Law God declared them justified ("NOT GUILTY!") in their conversion to Christ, their Promised Lord and Savior. The New Covenant writings from Matthew to Revelation - including John - were written to Jews and Jewish Christians.
Jesus was the lamb of God. Jesus was obedient to the Law of Moses and taught the people the spirit of the Law and He also fulfilled the Law of Moses. IF under the Law the high priest prayed for the Jews in covenant with God and offered sacrifices for the Jews in covenant with God, then Jesus as High Priest prayed for the Jews in covenant with God and offered Himself for the sins of the covenant people of God (John 17), then the salvation that Jonah said is of the LORD (Jonah 2:9), and the salvation which Jesus said was of the Jews was to and for the Jews in covenant with God and NOT for non-Hebrew Gentiles. Jesus said as much at the last Passover when He told the twelve disciples representing the twelve tribes of Israel that His body and blood are "given for you" then Jesus died in obedience to the Law of Moses, fulfilled the Law of Moses whose blood the high priest sprinkled upon the people and whose blood Jesus took away the sins of the Jewish people, then then salvation is of the Jews and no one else. There is nothing in the Law of Moses that the high priest offered sacrifices for Gentiles nor did Jesus as High Priest offer Himself for Gentiles but solely for the people of God in covenant with God.
4 But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law,
5
To redeem them that were under the law, that we might receive the adoption of sons. Gal. 4:4–5.
The Word of God - Genesis to Revelation - is to and for the Jewish people in covenant with God.
THAT IS the bottom line.