The liturgies are organised according to the traditional liturgical year and the calendar of saints. The sacraments of baptism and the Eucharist are generally thought necessary to salvation. Infant baptism is practised. At a later age, individuals baptised as infants receive confirmation by a bishop, at which time they reaffirm the baptismal promises made by their parents or sponsors. The Eucharist, consecrated by a thanksgiving prayer including Christ's Words of Institution, is believed to be "a memorial of Christ's once-for-all redemptive acts in which Christ is objectively present and effectually received in faith".