Then Yeshua would be a false prophet. Take the words of the Master Himself:
Mat 5:17 Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil.
Mat 5:18 For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.
Mat 5:19 Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them, the same shall be called great in the kingdom of heaven.
Mat 5:20 For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.
The words of YHWH are driven by precedent, unlike false religions which allow for addition after the fact (Roman tradition, Muslim Hadiths for instance). Yashua CANNOT have changed Torah, else He would have sinned against YHWH, and His perfect sacrifice would not be perfect. Likewise, His disciples, by the very definition, cannot abrogate the words of their Master.
St.John Chyrsostom comments showing that St. Paul is referring to the possibility of salvation for the Gentiles who don't keep the kosher laws.
The law has never been a means to salvation. Salvation has always been a matter of faith.
If you want to understand what St. Paul and Jesus were preaching against read about what the modern Orthodox Jews believe about the Law. They are literally the successors of the Pharisees.
Only the Pharisees survived the fall of the Temple.
http://www.chabad.org/library/article_cdo/aid/756399/jewish/The-613-Commandments.htm
The Catholic Church completely rejects the need to follow those laws that were abrogated in the NT.
And if the Law itself, handed down from Mt. Sinai by God Himself, could not save, no man made additions to that Law can save either.
If baptism could have saved, combined with faith, then why didn't God just do that from the very start? Why wait so long? If communion was required for salvation, why wasn't it incorporated into the Law from the beginning?
The Catholics whole premise that these things save is flawed from beginning to end. Their problem is that they don't stop to think through what their church teaches or bother comparing it to Scripture.
Salvation is indeed through faith alone. Thank God that it doesn't depend on our works and rituals.
Galatians 2:15-21 15We ourselves are Jews by birth and not Gentile sinners; 16yet we know that a person is not justified by works of the law but through faith in Jesus Christ, so we also have believed in Christ Jesus, in order to be justified by faith in Christ and not by works of the law, because by works of the law no one will be justified.
17But if, in our endeavor to be justified in Christ, we too were found to be sinners, is Christ then a servant of sin? Certainly not! 18For if I rebuild what I tore down, I prove myself to be a transgressor. 19For through the law I died to the law, so that I might live to God. 20I have been crucified with Christ. It is no longer I who live, but Christ who lives in me. And the life I now live in the flesh I live by faith in the Son of God, who loved me and gave himself for me. 21I do not nullify the grace of God, for if righteousness were through the law, then Christ died for no purpose.
Galatians 3:21-29 21Is the law then contrary to the promises of God? Certainly not! For if a law had been given that could give life, then righteousness would indeed be by the law. 22But the Scripture imprisoned everything under sin, so that the promise by faith in Jesus Christ might be given to those who believe.
23Now before faith came, we were held captive under the law, imprisoned until the coming faith would be revealed. 24So then, the law was our guardian until Christ came, in order that we might be justified by faith. 25But now that faith has come, we are no longer under a guardian, 26for in Christ Jesus you are all sons of God, through faith. 27For as many of you as were baptized into Christ have put on Christ. 28 There is neither Jew nor Greek, there is neither slave nor free, there is no male and female, for you are all one in Christ Jesus. 29And if you are Christ’s, then you are Abraham’s offspring, heirs according to promise.