In Christian belief and practice, a sacrament is a rite, instituted by Christ, that mediates grace, constituting a sacred mystery. The term is derived from the Latin word sacramentum, which was used to translate the Greek word for mystery. Views concerning both what rites are sacramental, and what it means for an act to be a sacrament vary among Christian denominations and traditions. The most conventional functional definition of a sacrament is that it is an outward sign, instituted by Christ, that conveys an inward, spiritual grace through Christ. The two most widely accepted sacraments are Baptism and the Eucharist (or Holy Communion), however, the majority of Christians also recognize five additional sacraments: Confirmation (Chrismation in the Orthodox tradition), Holy Orders, Confession, Anointing of the Sick, and Matrimony.Taken together, these are the Seven Sacraments as recognised by churches in the High church tradition—notably most Anglicans and some Lutherans, Roman Catholic, Eastern Orthodox, Oriental Orthodox, Independent Catholic and Old Catholic . Most other denominations and traditions typically affirm only Baptism and Eucharist as sacraments, while some Protestant groups, such as the Quakers, reject sacramental theology. Most Protestant Christian denominations who believe these rites do not communicate grace prefer to call them ordinances. The Holy Eucharist.
Justin Martyr described the Eucharist: And this food is called among us Eukaristia [the Eucharist], of which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined. For not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Savior, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of His word, and from which our blood and flesh by transmutation are nourished, is the flesh and blood of that Jesus who was made flesh. —Justin Martyr