Here is another mention of a holy day. Protestant commentators openly admit that when this verse is coupled with I Corinthians 5, it shows that, even at this late date, Paul was still keeping the "Jewish" (as they say) holy days, and they say he observed it along with Gentiles. Clearly, their conclusions on Paul's epistle to the Galatians do not agree with his practice with both Jews and Gentiles, as the book of Acts clearly shows.