For the day that’s in it;

Gaudete (English: /ˈɡaʊdeɪteɪ/ GOW-day-tay, Ecclesiastical Latin: [ɡau̯ˈdete]; “rejoice [ye]” in Latin)[a] is a sacred Christmas carol, thought to have been composed in the 16th century. It was published in Piae Cantiones, a collection of Finnish/Swedish sacred songs published in 1581. No music is given for the verses, but the standard tune comes from older liturgical books.

The Latin text is a typical medieval song of praise, which follows the standard pattern for the time – a uniform series of four-line stanzas, each preceded by a two-line refrain (in the early English carol this was known as the burden). Carols could be on any subject, but typically they were about the Virgin Mary, the Saints or Yuletide themes.

The complete text of “Gaudete“, including the refrain:

Gaudete by Collegium Vocale Bydgoszcz

By courtesy of Wikipedia;

https://en.wikipedia.org/wiki/Gaudete