Adoration is a sign of devotion to and worship of Jesus Christ, who is believed by Catholics to be present Body, Blood, Soul, and Divinity, under the appearance of the consecrated host, that is, sacramental bread. From a theological perspective, the adoration is a form of latria, based on the tenet of the real presence of Christ in the Blessed Host.
Christian meditation performed in the presence of the Eucharist outside Mass is called Eucharistic meditation. It has been practiced by such as Peter Julian Eymard, Jean Vianney and Thérèse of Lisieux. Authors such as the Venerable Concepcion Cabrera de Armida and Blessed Maria Candida of the Eucharist have produced large volumes of text based on their Eucharistic meditations.
When the exposure and adoration of the Eucharist is constant (twenty-four hours a day), it is called perpetual adoration. In a monastery or convent, it is done by the resident monks or nuns and, in a parish, by volunteer parishioners since the 20th century. In a prayer opening the Perpetual chapel in St. Peter Basilica, Pope John Paul II prayed for a perpetual adoration chapel in every parish in the world. Pope Benedict XVI instituted perpetual adoration for the laity in each of the five sectors of the diocese of Rome.
Eucharistic adoration may be done both when the Eucharist is exposed for viewing and when it is not. It may take place in the context of the liturgical rite of Exposition of the Blessed Sacrament or an informal "visit" to pray before the tabernacle. Writer Valerie Schmalz notes that "During the first part of the twentieth century, it was common for Catholics, young and old, on their way home from work or school, en route to the grocery store or a sports practice, to "stop in for a visit" to the Blessed Sacrament in their local church. Most times the Eucharist was not exposed, but a red candle–then, as now–showed the Presence in the tabernacle."
Eucharistic exposition and benediction is a complete liturgical service in its own right, and an extension of what is celebrated in the Eucharist. At the beginning of the exposition of the Blessed Sacrament, a priest or deacon removes the sacred host from the tabernacle and places it in the monstrance on the altar for adoration by the faithful. A monstrance is the vessel used to display the consecrated Eucharistic Host, during Eucharistic adoration or benediction.