As we enter Holy Week, I want to share one of the Church’s most ancient rituals with you.

The Holy Week service called Tenebrae has become so rare today many Christians have never experienced the funereal tenor of this sorrowful ritual. The first Tenebrae service I attended made such a profound impact on me I had to learn more about it.

It began in the Middle Ages. Imagine it’s Good Friday in the year 715 AD. An imposing monastery towers over a small medieval town as the sun rises above the patchwork of fields and farms. The monks usually rise at dawn to begin their day with Matins, one of eight hours scheduled in each day during which they pray the Divine Office. But on this Friday in Holy Week, the monastery will offer two canonical hours (Matins and Lauds) together in the evening, so the village faithful can join the monks in a service to recall Christ’s last hours. The ritual is called Tenebrae, which means shadows or darkness.

The villagers enter the sanctuary, which is illuminated only by 15 candles lined up and down the large triangular candlestick holder mounted on a column.

This is the Tenebrae hearse, and it stands beside the altar.

Surrounded by cold stone walls, villagers and monks shiver in this chilly spring evening, as they silently recall that awful death over 700 years ago. The service that begins in candlelight will end in near darkness.

Amazingly, this medieval ritual of shadows has survived the centuries in the Western church and, depending on the denomination, or even the particular church, different verses of the Bible and hymns are recited and sung to recall Jesus’ last hours from the Last Supper to his sacrifice on the Cross.

I’ll never forget my first Tenebrae experience. Upon entering the sanctuary, I noticed that someone had covered the windowpanes in the doors to the worship center with black. The church was dim. I walked toward the altar on which stood seven candles on either side of a larger candle, called the Christ candle. Sliding into the pew next to my friend, I noticed that the large cross looming over our altar had been shrouded in black. I turned to her; she smiled, but said nothing. This was not a time to speak.

The choir wore black attire, as if they were at a funeral. The pastor entered from the back of the church with his acolyte, and they mounted the steps to the altar.

Ancient words — some Psalms, some from Lamentations, some from the Gospel of John — interspersed by prayer, led the faithful through Christ’s last hours. At intervals we joined the choir and sang hymns such as Oh Sacred Head So Wounded, and When I Survey the Wondrous Cross. In other churches, perhaps the choir would sing much older music such as the Kyrie Eleison (“Lord Have Mercy, Christ Have Mercy, Lord Have Mercy.”)

After each set of Scripture readings and worship, the acolyte extinguished one more candle, until the only light in the church came from the central Christ candle.

Somber darkness hovered over us as the Christ candle tossed flickering shadows against the wall behind our altar. The tension was almost palpable. Suddenly, the pastor slammed the large Bible shut, sending a retort like a gunshot through the church. I jumped, startled, at what I was to learn later was the strepitus, or loud sound. In some churches, a person slams a breviary or hymnal against the pew, or stomps on the floor to create the strepitus. Reminding us of the finality of Christ’s sacrifice, some say it could symbolize the earthquake at the moment of his death or the stone as it struck against the opening of Christ’s tomb, sealing him inside.

It was over, and we left the sanctuary in silence. I felt deeply moved, as if I were walking away from the grave of a loved one. Yet the Christ candle continued to burn, as a reminder of Christ’s coming resurrection.

I’m so thankful that of all the sacred rituals that have blessed the Western church over the centuries, only to disappear over time, we have somehow managed to keep this one.