Besides the solemn two days after Christmas, the Church commemorates the attempt to put St. John to death in a caldron of boiling oil outside the Latin Gate. The saint came from it unhurt, and even more vigorous than before. A church now marks the site which a late tradition assigns to this event. This feast celebrates the martyrdom of the evangelist who, according to the prophecy of the Savior, was also, like his brother, to drink of the chalice of the Passion, in order that he might have the right to one of the highest thrones in the Messianic kingdom, which his mother had begged for him.
(Source: The New Roman Missal by Father Lasance)
Commentary: St. John was the only apostle to join the Blessed Virgin Mary and Mary Magdalen at the crucifixion of our Lord Jesus Christ at Calvary. At the time he was still in his teens. In addition to writing the Gospel of St. John, he is also the author of the Book of the Apocalypse.