Luther, commenting on Ephesians 5, notes that frivolity does not serve the things of God. He especially has in mind wasting time in the sermon with silly stories to the neglect of better things.
It always happens when many people come together that, even though they begin with serious matters, they soon fall into frivolous, loose, ridiculous stories, with which they waste time and neglect better things. For instance, at Easter they mix foolish, ridiculous stories into the sermon in order to wake up the sleeping. At Christmas, they rock a baby and practice their nonsense with rhymes. They do the same thing with [the festival of] the three holy kings [Epiphany], the Passion of Christ, Dorothy, and other saints (AE 76:386–387).