“…there can be many purposes for one work.  We use the Lord’s Supper as a sacrament inasfar as it is a testimony by which faith is guided.  Second, this faith itself with the outward participation in the sacrament is a kind of sacrifice, because God pronounces that this faith, and exercises of this kind, in the New Testament are sacrifices of praise and a form of worship.  Thus this spiritual obedience itself becomes a kind of sacrifice by which honor is given to God, which He requires and approves.  Then, since with this faith there is of necessity joined the giving of thanks for the highest benefit which He has bestowed upon us and the church, thus it is called a eucharistia (a sacrifice of thanksgiving).  Besides this there is also the need for confession; for we have shown that we believe the Gospel and should invite others to follow our example.  All these things are eucharistic sacrifices.  Therefore the ancients called this ceremony [the Lord’s Supper] a sacrifice.”

Philip Melanchthon, Loci Praecipui Theologici 1559.  Translated by J.A.O. Preus, 2nd edition.  2011, St. Louis: Concordia Publishing House.  282-283.