The New Covenant is not a covenant of sin but of faith righteousness and salvation like being neither hot nor cold is the teaching of the traditional Church they are not in one covenant or the other which leads to confusion and a inability to evangelise effectively the blood of Jesus is shed for all Mankind so that all who believe on him He gave the power the right the ability to become the Children of God even those who believe on His name.
Not through the observance of the Law of Moses but through the Grace of God, it is for the individual to freely choose that which is permissible to observe with the guide of four exceptions ,
Acts 15:19-29
Wherefore my sentence is, that we trouble not them, which 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. [22] Then pleased it the apostles and elders, with the whole church, to send chosen men of their own company to Antioch with Paul and Barnabas; namely, Judas surnamed Barsabas, and Silas, chief men among the brethren: [23] And they wrote letters by them after this manner; The apostles and elders and brethren send greeting unto the brethren which are of the Gentiles in Antioch and Syria and Cilicia: [24] Forasmuch as we have heard, that certain which went out from us have troubled you with words, subverting your souls, saying, Ye must be circumcised, and keep the law: to whom we gave no such commandment: [25] It seemed good unto us, being assembled with one accord, to send chosen men unto you with our beloved Barnabas and Paul, [26] Men that have hazarded their lives for the name of our Lord Jesus Christ. [27] We have sent therefore Judas and Silas, who shall also tell you the same things by mouth. [28] For it seemed good to the Holy Ghost, and to us, to lay upon you no greater burden than these necessary things; [29] That ye abstain from meats offered to idols, and from blood, and from things strangled, and from fornication: from which if ye keep yourselves, ye shall do well. Fare ye well.