The Bible considers the apostle and evangelist John to be the author of the gospel according to John (John 21:14), The Letters of John, and the Book of Revelation. He is frequently identified with the son of Zebedee and brother of James (John 21:2), who used to belong to the inner circle of the disciples and eventually a pillar of the community in Jerusalem (Gal 2:9). Some believe, he is identical with the “Beloved disciple” (John 13:23; 29:26), to whom Jesus entrusted his mother and who testified to the side of Jesus being pierced on the cross.
A tradition affirms, he later worked in Ephesus and was exiled on the island of Patmos under the emperor Domitian, where he composed the Book of Revelation. After his return from Patmos to Ephesus, he is believed to compose the gospel the letters, and eventually, die around the year 100. His grave was venerated in Ephesus as early as around the year 200.
His liturgical veneration started in connection with his brother James and was first attested in the 4th century in the Christian East. A legend says, he converted a pagan priest, after he drank a glass of poisoned wine without suffering any hurt. This legend combined with germanic pagan drinking cultic customs gave rise to the blessing and sharing of Saint John’s wine, accompanied by the words: drink the love of Saint John.
The Catholic liturgy offers readings from 1 John 1:1-4 and John 21:20-24. The liturgical prayers speak about the mystery of the eternal Word that became flesh and thus link with the Christmas liturgy.