Lots (but not all) of the Levitical law was superceeded by the New Covenant.
All food restrictions were lifted, for example.
http://www.auburn.edu/~allenkc/fbf/compare.html
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Basically, a lot of what we consider "Jewish" today was the norm for the Christians of the time of Christ.
Since the New Covenant, however, Christians don't
have to be circumcised

or practice other ceremonial laws because they obey them in their hearts.