I recently happened upon the image above, which comes from a thirteenth-century illuminated manuscript of the Book of Revelation known as the Douce Apocalypse. The manuscript is in the Bodleian Library at Oxford University; it is named after Francis Douce, who bequeathed his collection to the library at his death in 1834.
The illustration depicts the adoration of God with the Lamb from Revelation 7:9-14.
After these things I looked, and behold, a great multitude which no one could count, from every nation and all tribes and peoples and tongues, standing before the throne and before the Lamb, clothed in white robes, and palm branches were in their hands; and they cry out with a loud voice, saying,
“Salvation to our God who sits on the throne, and to the Lamb.” And all the angels were standing around the throne and around the elders and the four living creatures; and they fell on their faces before the throne and worshiped God, saying,
“Amen, blessing and glory and wisdom and thanksgiving and honor and power and might, be to our God forever and ever. Amen.”
Then one of the elders answered, saying to me, “These who are clothed in the white robes, who are they, and where have they come from?” I said to him, “My lord, you know.” And he said to me, “These are the ones who come out of the great tribulation, and they have washed their robes and made them white in the blood of the Lamb.
In this manuscript illustration, we see St. John standing at the left side outside the frame, holding a copy of his book, as the elder pictured in the window explains to him that those in the white robes have survived the tribulation and washed their robes white in the blood of the Lamb. The Lamb signifies the crucified Christ whose blood purifies the faithful from all sin. The central image shows a mandorla encasing God enthroned with the Lamb. They are surrounded by the symbols for the four Gospel writers at each corner: Matthew as the winged man, John as the eagle, Luke as the ox, and Mark as the lion. In four horizontal registers we see saints or angels with halos at the top; next the twenty-four elders in prostrate worship; and the multitudes holding palm branches in the two bottom registers. All except John and God wear white, symbolizing victory and resurrection. The palm branches also signify victory and evoke Christ’s triumphant entry into Jerusalem on Palm Sunday, showing that the worshipers are now in the heavenly Jerusalem. Here, they are worshiping loudly, crying out their praise and thanks to God and their Savior, the Lamb. This is the promise held out to all who remain faithful to the Lamb.