Wasn't the New Covenant (NC) supposed to have "abolished" the Mosaic laws of the Old Covenant (OC)? Who was the NC available to? Were Jewish Christians beneficiaries of both the OC and the NC, or just the NC?
Now, read the following verses, taken from Acts 21, to get a sense of my questions above:
20 When they heard this, they praised God. Then they said to Paul: "You see, brother, how many thousands of Jews have believed, and all of them are zealous for the law. 21 They have been informed that you teach all the Jews who live among the Gentiles to turn away from Moses, telling them not to circumcise their children or live according to our customs. 22 What shall we do? They will certainly hear that you have come, 23 so do what we tell you. There are four men with us who have made a vow. 24 Take these men, join in their purification rites and pay their expenses, so that they can have their heads shaved. Then everybody will know there is no truth in these reports about you, but that you yourself are living in obedience to the law. 25 As for the Gentile believers, we have written to them our decision that they should abstain from food sacrificed to idols, from blood, from the meat of strangled animals and from sexual immorality."
26 The next day Paul took the men and purified himself along with them. Then he went to the temple to give notice of the date when the days of purification would end and the offering would be made for each of them.
Basically, Paul, upon being confronted about his teaching of quintessence of the NC, backs down and performs OC rituals and cereminies. Why did he do this? Did he not believe in what he taught?
As if that was not OC enough, Paul even goes to the Temple and anounces the day of the end of the purification ceremonies, on which day offerings would be given. Are these not OC ritualims? Basically, he is showing complete allegiance to the OC here.