@Adám Maybe I'm playing devil's advocate here, but I'm not 100% sure that Christians
do keep the Ten Commandments. For instance, Paul says in
Romans 14, "One person considers one day more sacred than another; another considers every day alike. Each of them should be fully convinced in their own mind." This certainly seems to refer to the (non)observance of Jewish holy days; but does that include the Sabbath too? I'm not sure.