In his book With, author Skye Jethani describes the mausoleum of Galla Placidia in Italy:

Fifteen hundred years ago, the emperor of Rome built a tomb for his beloved sister. The small building was designed in the shape of a cross with a vaulted ceiling covered with mosaics of swirling stars in an indigo sky. The focal point of the mosaic ceiling was a depiction of Jesus the Good Shepherd surrounded by sheep in an emerald paradise.

The mausoleum of Galla Placidia still stands in Ravenna, Italy, and has been called “the earliest and best preserved of all mosaic monuments” and one of the “most artistically perfect.” But visitors who have admired its mosaics in travel books will be disappointed when they enter the mausoleum. The structure has only tiny windows, and what light does enter is usually blocked by a mass of tourists. The “most artistically perfect” mosaic monument, the inspiring vision of the Good Shepherd in a starry paradise, is hidden behind a veil of darkness.

But the impatient who leave the chapel will miss a stunning unveiling. With no advance notice, spotlights near the ceiling are turned on when a tourist finally manages to drop a coin into the small metal box along the wall. The lights illuminate the iridescent tiles of the mosaic but only for a few seconds. One visitor described the experience: “The lights come on. For a brief moment, the briefest of moments—the eye doesn’t have time to take it all in, the eye casts about—the dull, hot darkness overhead becomes a starry sky, a dark-blue cupola with huge, shimmering stars that seem startlingly close. ‘Ahhhhh!’ comes the sound from below, and then the light goes out, and again there’s darkness, darker even than before.”

The bright burst of illumination is repeated over and over again, divided by darkness of unpredictable length. Each time the lights come on, the visitors are given another glimpse of the world behind the shadows, and their eyes capture another element previously unseen—deer drinking from springs, Jesus gently reaching out to his sheep that look lovingly at their Shepherd. After seeing the mosaic, one visitor wrote: “I have never seen anything so sublime in my life! Makes you want to cry!”

Possible Preaching Angle:

It is difficult to experience the glory of God in our daily lives and when we do, it is only for brief moments. Yet, there are time when God breaks through the darkness of this world and reveals himself for a brief moment. Like Isaiah’s experience (Isa. 6:1-5), these moments should be life changing.