Holy Eucharist Teachings by the Fathers of the Church
Our Lord Jesus took in His hands what in the beginning was only bread; and He blessed it, and signed it, and made it holy in the name of the Father and in the name of the Spirit; and He broke it and in His gracious kindness He distributed it to all His disciples one by one. He called the bread His living Body, and did Himself fill it with Himself and the Spirit. And extending His hand, He gave them the Bread which His right hand had made holy: "Take, all of you eat of this, which My word has made holy. Do not now regard as bread that which I have given you; but take, eat this Bread [of life], and do not scatter the crumbs; for what I have called My Body, that it is indeed. One particle from its crumbs is able to sanctify thousands and thousands, and is sufficient to afford life to those who eat of it. Take, eat, entertaining no doubt of faith, because this is My Body, and whoever eats it in belief eats in it Fire and Spirit. But if any doubter eat of it, for him it will be only bread. And whoever eats in belief the Bread made holy in My name, if he be pure, he will be preserved in his purity; and if he be a sinner, he will be forgiven." But if anyone despise it or reject it or treat it with ignominy, it may be taken as a certainty that he treats with ignominy the Son, who called it and actually made it to be His Body.
Holy Eucharist teachings by the Fathers of the Church - St Ephraim (c. 306 - 373 A.D.)