The writings of St. Bernard, the famous Abbot of Clairvaux, who was born in 1091, became a monk at Citeaux in 1113, founded the monastery of Clairvaux in 1115, and died in 1153, considering their large amount, contain surprisingly few allusions to the Eucharist. But there is sufficient to show his agreement with the writers of his time in general in their insistence on the reality of the body and blood of Christ in the Eucharist and on the spiritual character of this presence. In one of his Letters he speaks of the effect of consecration being to make the bread and wine the body and blood of Christ, and expresses his opinion that in a case where through forgetfulness there was no wine in the chalice the bread had none the less been made Christ’s body by the consecration. In his Life of St. Malachy, the Archbishop of Armagh, he refers incidentally to the celebration of the Eucharist as the offering of “the living Bread from heaven”; and tells of the refutation by St. Malachy of one who had “presumed to say that in the Eucharist there is only a Sacrament and not the fact (rem) of a Sacrament, that is, only the blessing and not the reality of the body”. In his Sermons he says that “the Bread which came down from heaven and gives life to the world, namely the body of the Lord Jesus,” “the new flesh of the resurrection,” is received in Communion; that “the flesh of the Lamb” “is given to us spiritually not carnally”; that “the real substance of the flesh itself is undoubtedly present to us in the Sacrament”; and that, though in the Sacrament we have the Word in the flesh and as a reality, yet “without spirit even the Sacrament is taken to judgment, and the flesh profits nothing, and the letter kills, and faith is dead”.
Robert Pulleyn, afterwards Cardinal and Chancellor at Rome, was teaching at Oxford in 1133. The eighth book of his Sentences contains some discussions about the Eucharist. It is spoken of as a sacrifice. At the institution our Lord consecrated bread and wine to be His body and blood. As then given, the sacrament was the mortal body of the Lord, but was possessed of the qualities of His immortal body. At the consecration the bread and wine are converted into the body and blood of Christ, so that they pass into a different nature. The substance of bread and wine ceases to be, but the properties which the senses can discern remain. Christ is taken whole in each part of each species. At the breaking of the consecrated Sacrament, the body of Christ is not broken. The special significance in the blood is of the soul. The reception by the laity in one kind only is a matter within the competence of the Church to decide; and in receiving the flesh of Christ they receive also His blood.
Peter the Venerable became Abbot of Cluny in 1122 and died in 1156. Among his writings is a treatise against the followers of Peter of Bruis, who had denied that the Eucharist is a rite of value which ought to be retained in the Church. The substances of the bread and the wine, it is here said, are converted into the real body and blood of the Lord. This change of substance takes place by the power of the Word of God; it does not involve a change of species or form. The Sacrament is a sign which is what it denotes, a reality and not a shadow or figure. By it Christ is present not only as God but also as man. When His flesh is eaten, He remains unbroken, immortal, incorruptible, the Object of adoration, and by means of His immortal body He leads those who are mortal to immortality. The reality of His flesh and blood remains hidden in the species of bread and wine. He gives His flesh and blood not only to be honoured and adored but also to be eaten and drunk, so that this spiritual food and drink may enable men to attain to a blessed immortal life. In this sacrament the Church has a sacrifice, and in it offers the body and blood of its Redeemer. The sacrifice of Christians throughout the world is one; and the Lamb of God, who takes away the sins of the world, is the only Victim on Christian altars. It is a presentation of the passion and death of the Lord. It was once for all offered on the cross, and is ever offered on the altar. It was instituted in order that there might be a means to preserve the memory of Christ. Although He is offered on the altar, and although there is a presentation of His death, He does not suffer pain or death. If it asked why it is a presentation of His death rather than of His resurrection or ascension, the answer is that by His death He restored life to the dead and saved the world. The presentation is made through the presence on the altar of the flesh which suffered on the cross, and the blood which then was shed. There is in it a renewal of redemption, and a daily remission of sins to those who are penitent.