"Have yourself a merry little Christmas" is a line from the famous Christmas song "Have Yourself a Merry Little Christmas." It is a wish for someone to have a joyful, peaceful Christmas celebration. The song was written by songwriters Hugh Martin and Ralph Blane, and it has become a beloved classic that has been covered by many artists over the years. It is a reminder to cherish the small moments of the holiday season and to make the most of the time spent with loved ones.