The Apostles were commissioned to go all over the world to preach, teach, baptize those who believed the good news of salvation offered to every willing person in John 3:16. They were to teach Jewish values to the world as Jesus says that 'salvation is from the Jews' in John 4:22 and make all the nations disciples just like they are disciples of Jesus (Matthew 28:18-20). The Jewish values are found in Moses and the Prophets (Luke 16:27-31) and confirmed in Mathew 5:17-18 as unchangeable from Moses until the end of the world. The message of repentance and remission of sins was a new message to both Israel and the world (Mark 1:4, Luke 24:47).
Therefore, anyone who claims to accept Jesus as their personal Savior but reject anything in Moses like the Sabbath day and other things has not accepted the real Jesus who says that nothing in Moses can change, that is, what was forbidden is still forbidden, what was permissible is still permissible, unless Jesus specifically spoke of a change like for 'eye for eye' or 'go and sin no more'.
Jesus also says that those who can hear and understand the message of repentance, remission of sins, and total obedience to Moses and the Prophets because salvation is from the Jews will gather into one flock or fold under Him as the Shepherd or Pastor.
The flock or the fold will adopt the Moses and the Prophets (which contains the Jewish values) and live accordingly as it has been required of the Jews since Moses. Believers in Jews have joined the Mosaic Jewish culture to fulfill the vision of Jesus of one body of believers under Him.
Ye worship that which ye know not: we worship that which we know; for salvation is from the Jews. John 4:22 ASV
and that repentance and remission of sins should be preached in his name unto all the nations, beginning from Jerusalem. Luke 24:47 ASV
John came, who baptized in the wilderness and preached the baptism of repentance unto remission of sins. Mark 1:4 ASV
And other sheep I have, which are not of this fold: them also I must bring, and they shall hear my voice: and they shall become one flock, one shepherd. John 10:16 ASV
And it is easier for heaven and earth to pass than one tittle of the law to fall. Luke 16:17 DRB
For amen I say unto you, till heaven and earth pass, one jot, or one tittle shall not pass of the law, till all be fulfilled. Matthew 5:18 DRB
(12) For as the body is one, and hath many members, and all the members of the body, being many, are one body; so also is Christ. (13) For in one Spirit were we all baptized into one body, whether Jews or Greeks, whether bond or free; and were all made to drink of one Spirit. (14) For the body is not one member, but many. 1 Corinthians 12:12-14 ASV