The New Testament shows that Paul remained an observant Jew even after coming to faith in Messiah:

• Acts 21:20- Having been accused of teaching Jews to abandon the Torah, Paul takes some other men with him to the temple to observe purification rites, in order to prove that he is “living in obedience to the Torah.”
• Acts 24:17-18 – Paul testifies that his intent was to present offerings, and that he was ceremonially clean (in accordance with the Torah)  1 Cor 9:18-23 -- Paul became as one under the law (Torah) to win those under the law. Paul repeatedly made it clear, however, that Torah-observance is not a means of salvation, and should not be imposed on Gentile believers at all:
•   Galatians – (The whole book!)  Romans 3:20 – No one will be declared righteous by observing the law.
• Gal 2:14 – Paul confronts Peter for forcing Gentiles to follow Jewish customs. (See also Acts 15:1-21)
• Acts 21:25 – James agrees that Gentile believers should not be compelled to observe the Torah, at the same time as he urges Paul to demonstrate to the Jews of Jerusalem that he (as a Jew) is observant.
• Col. 2:16-17 – Don’t let Sabbaths and feast days become an issue. Paul does not advocate that Jewish believers should abandon their observance: 1 Cor 7:18 – Paul tells the circumcised not to seek to become uncircumcised. This could be construed as meaning that those brought up as observant Jews should not abandon it. At the same time, non-Jewish believers should not convert to Judaism.
• 1 Cor 9:21 – Paul considers himself to be under the Law (Torah) of Messiah (rather than the Law of Moses)
• Gal 2:25 – “we are no longer under the supervision of the law (Torah)”
• Col 2:14 – God has canceled the written code
• Gal 3:10 – All who rely on observing the law are under a curse.

The bottom line seems to be that Observing the Torah is not wrong, but thinking it can buy salvation is wrong. There is no benefit in subjecting oneself to the legal code after embracing the Grace of God through Messiah. It should probably also be pointed out the Torah Paul kept is not the same as Rabbinic Judaism today. Rabbinic Judaism is Torah plus endless “traditions of men,” and I doubt Paul had much concern for these.

Paul continued to keep the Temple rites which God had prescribed through Moses and had not specifically said to stop. Since the destruction of the Temple in 70 AD, however, it has not been possible for even the strictest Jew to keep these observances. This seems evidence enough that God is finished with the sacrificial system and does not expect anyone to observe it.