We celebrate Pentecost 50 days after Jesus' resurrection. It commemorates the arrival of the promised Holy Spirit, our comforter. We see this detailed in Acts 2 where "God-fearing Jews from every nation" were staying in Jerusalem.
In the dome of the cathedral of Cefalú there is a magnificent mosaic of Jesus. Towering overhead in sparkling gold and azure, Christ raises his right hand in blessing while he holds in his left hand the Gospel of John, open to the words, “I am the light of the world.”