BACK BAY -- More than 500 worshipers packed St. Clement Eucharistic Shrine in Boston’s Back Bay for a Mass celebrated by Cardinal Seán P. O’Malley to mark the return of perpetual eucharistic adoration to the city after a 40 year absence.

The standing room only Mass was held Aug. 15, the Feast of the Assumption of the Virgin Mary. In his homily, the cardinal highlighted the importance of beginning the adoration on that day.

“As we inaugurate this perpetual adoration of the Eucharist in this shrine, we do so on the great Marian Feast when we celebrate Mary as the arc of the covenant, leading us on our pilgrimage to our heavenly home,” Cardinal O’Malley said.

Mary, he said, is “the living tabernacle, who carried the body of Christ and then gave Christ’s body to us so that that body can become our Eucharist.”

The celebration concluded with a eucharistic procession through the aisles of the church and a brief period of adoration.

Congregants were invited to a reception following the Mass featuring light refreshments and information on how to participate in the perpetual adoration.