This window portrays the revelation which Saint John the Divine had on the Isle of Patmos.

In the book of the Revelation, St John the Divine relates how, when "in the Spirit on the Lord's Day" he was commanded to write in a book that which was revealed to him in a vision. In this window St John is seated with his Eagle (a symbol of the Gospel) by his side, describing his vision of Our Lord ; seated on a throne set in heaven, and of how "there was a rainbow round about the throne, in sight like unto an emerald" and of how he saw the four and twenty elders sitting round about the throne, clothed in white raiment, and on their heads crowns of gold.

Beneath the realistic depiction of this scene is the Altar bearing "the Lamb that was slain" and underneath the Altar are "the Souls of them that had been slain for the word of God." The seven Candles represent the seven churches to which St John was commanded to write.

The use of symbols in stained glass, sculpture and woodwork is said to have originated in the reluctance of early Christians to write the sacred names at length. This it was considered irreverent to do, and indeed often highly dangerous; and so, for example, St John was represented by an Eagle, St Peter by two crossed keys, the Holy Spirit by a Dove, and Eternity by a circle or a ring - something without beginning or end.