The altar of repose is an altar in a Roman Catholic or Anglo-Catholic church used as the place where the Communion hosts, consecrated in the Mass of the Lord's Supper, are reserved for Holy Communion on the following day, which is Good Friday, the day on which the death of Christ is observed liturgically and Mass is not celebrated, so communion must be given from Hosts consecrated on the previous day.
The Roman Catholic Church does not prescribe that the place of reservation should have an altar, requiring only that "the Blessed Sacrament should be reserved in a closed tabernacle or pyx". Indeed, the Church's rules on the matter envisage no more than a single altar in the church.
In the Mass of the Lord's Supper sufficient hosts are consecrated for the faithful to receive Communion both at that Mass and on the next day. The hosts intended for the Good Friday service are not placed in the tabernacle, as is usual, but are left on the altar, while the priests says the postcommunion prayer. They are then carried in solemn procession to a place of reservation somewhere in the church or in an appropriately adorned chapel. The priest uses a humeral veil while carrying them to that place. The procession is led by a cross-bearer accompanied by two servers with lighted candles; other servers with lighted candles follow and a thurifer immediately precedes the priest. The Blessed Sacrament remains in the temporary place until the Holy Communion part of the Good Friday liturgical service.
Roman Catholic piety has made Holy Thursday a day of exceptional devotion to the Blessed Sacrament, and the place where the Sacrament is reserved is a focus point for the love and aspirations of the faithful. Eucharistic adoration is encouraged at the place of reservation, but if continued after midnight should be done without outward solemnity.
After the Good Friday service, the Blessed Sacrament remains available as viaticum for the dying and for Communion given on Good Friday at the service called The Celebration of the Passion of the Lord. While the Blessed Sacrament remains in the temporary tabernacle, a lamp or candle is kept burning before it.
Mention of the altar of repose and the procession to it is not found before the close of the fifteenth century. The reservation of the Consecrated Species in the Mass of Holy Thursday, spoken of in earlier liturgical works, was for the distribution of Holy Communion, not for the service on the following day.