What were the practices observance of which was abhorred by St Paul in Gal 4:9-10?

In Galatians 4:9-10 we see St Paul sending a terse message to the faithful abhorring their observance of days, months, seasons and years terming them weak and beggarly elements. Unfortunately, he does not specify what those elements are. In fact, Jewish traditions mandated the observance of feasts and spells of prayer, determined by the days, seasons etc. Jesus followed them . Evidently, St Paul was referring to something else. My question therefore is ; what were the practices observance of which was abhorred by St Paul in Gal 4:9-10 ? Inputs from scholars of any denomination are welcome.