The sacrament of the Eucharist was originally a teaching of primitive Christianity about the way by which the human soul could achieve spiritual oneness with the Christ within -- a ray, as it were, from the Cosmic Christ -- thereby becoming a god-man when this union or yoga was complete.
Other religions speak about the Buddha within, and the cosmic Buddha, not meaning Gautama, the Hindu teacher, but a Cosmic Buddha of which Gautama was a ray, as Jesus the Avatara was a ray of what the Christians call the cosmic Christ.
In a very short time, due to a number of converging causes, this beautiful and really holy Christian teaching of how to achieve this yoga or union became lost in the Christian Church, and was replaced by a ceremonial. In other words they substituted a ceremony, a ritual, a rite, to replace the occult esoteric teaching which had been forgotten except by the very few. These very few were attempting to hold back, as it were, or to restrain, the complete loss of the wonder out of the bosom of the Christian Church and from Christian thought. Many of them were originally pagans who were attracted to the new Theosophical Society -- as earliest Christianity was -- because they felt it had a new dispensation of spiritual power in it; and they took the Eucharist out of the ceremonies of the Mysteries of Dionysus. The Dionysiacs, the Dionysian Mysteries, had a communion in which the priests and the congregation together partook of the blood and of the flesh of their divinity Dionysus. The blood was wine, the flesh was the cereal, bread if you wish, or wheat.
Now the Christians took this over because they knew something of the inner meaning of this Dionysian symbol; and that is the origin of what the Christians even today, carrying on a tradition but forgetting the original verities, call the holiest mystery in the Christian Church -- as it originally was.
Why, even today we can say that the most sacred teaching we Theosophists have, our most sacred mystery, our most occult effort, is so to live and think and study and be trained, that the individual man may become at one with the divine. We are on the upward arc, so that now we can bring about this union -- some individuals more than others. When the union is complete you have what we call a Buddha or a Christ. When the union is less complete, you have a Mahatman or one of the greatest chelas. When the union is still less complete, you have some of the great men of human history, mostly in the philosophic and religious lines: great thinkers and teachers such as Pythagoras, and Plato, and Empedocles and other sages from Egypt and Syria and in the Druidic lands of Germany and France and Britain; or again in Persia. Then on a still lower scale you have those men who have caught the gleams of the vision sublime and have been so enraptured by the picture of that glimpse that their whole life thereafter becomes consecrate to the glory. These are chelas and the great men of the human race. We can all become such, more or less.
Here is a final thought about this: When the Dionysiacs spoke of drinking the blood of their god in the wine and taking the flesh into themselves through the cereal, the wheat or the bread, they never intended it in the literal way in which it is now accepted in the old-fashioned orthodox Christianity. They intended it in a mystical sense which I will now proceed to explain. The blood of the god, in the ancient countries surrounding the Mediterranean Sea always meant the cosmic vitality, what we call Jiva, the life, the Divine Life. Thus the blood, but the word was used as is found even in the Mosaic books of the Jews: "in the blood is the life." The blood became the symbol for the life of the Christ, the Christ's life, the Christ's vitality, the divine vitality in individual man which transformed him and raised him so as to become one with the Christ or with the Buddha. In that sense, by training, by effort, by yearning, by study, the neophyte raised his own life to aspire upward, to become universal, to become one with the universal life. And they called this union, or yoga, 'communion': the man thereafter communed with the cosmic spirit. "I and my Father are one," said Jesus.
And the bread, the cereal, wheat, in ancient times always had the symbolic meaning of intellect, intellectual power. Here is where you get a very interesting side-line for those who are technical Theosophical students. The ancients said that wheat was originally brought to this earth from the planet Venus. Now the planet Venus in the common scheme represents what we humans in the human constitution call the higher manas, in which the Christ in us, or the Buddha in us, works. The vine, said the Ancient Greeks and Latins, originally came from the planet Jupiter. The planet Jupiter, they said, is that which controls our vitality, or anima, or Jiva, our life. And Jiva is a direct efflux from Atman.
These many and converging and correlated lines of ancient Mediterranean thought the earliest Christians seized hold of and put together and welded fast into a lovely and marvelous teaching of union; and then later when the truth became lost, they collected the Dionysian thoughts, changed them slightly, gave them new names, and you have the Christian communion as a ceremonial rite in the Church, commemorating the process by which the sincere Christians, or one 'infilled with the Christos' becomes at one with the divine.
This very word 'Christian' originally meant one who is filled with Christ, one who had evoked the Christ in himself by that union, that yoga, the communion, the very thought I am trying to bring forth. Originally Christians were not called Christians. They did not dare call themselves by the title of their great Avatara. It would be exactly as if we were to call ourselves Buddhas, if Buddha were our teacher. Christians originally called themselves Chrestoi, a Greek word which meant 'worthy ones,' or as we would phrase it today, students, learners, disciples of the Christ; and the Christians themselves tell us that they were first called Christians at Antioch in Syria; and heaven knows when that was! It may not have been until the third or fourth century.