On page 575 of "Science and Health with Key to the Scriptures" Mrs. Eddy states that "spiritual teaching must always be by symbols." Then to understand something of the nature of such symbols must be of importance to the student of Christian Science. The word "symbol" comes from the Greek verb meaning to throw with or together, to compare, as by apt illustration, a figure of speech, or an object presenting associated ideas. It is defined, in a narrow sense, as a visible sign or representative of an idea or a quality. Its synonyms, derived from the same Greek root, are emblem and parable. The word "compendium," which we get from the Latin words meaning to hang together, and which is defined as the substance of any subject abridged to a small compass, more nearly expresses the religious connotation of the word symbol, a thing or an idea representative of Spirit. For instance, in saying that "on these two commandments hang [or depend] all the law and the prophets," Jesus expressed the idea that this abbreviated statement comprehends the whole of the preceding Hebrew teaching as to correct relations between God and man.
Jesus' purpose in thus compressing "the law and the prophets" into a concise, comprehensive form, was to extract from the multitude of words with which interpretation had encumbered even the Commandments, the clear essence, or spiritual meaning of these. It was plainly his design to reveal God's fatherhood to man as simply and clearly as possible, yet we are told that "without a parable spake he not unto them," and he elsewhere said to his students, "Unto you it is given to know the mysteries of the kingdom of God: but to others in parables; that seeing they might not see, and hearing they might not understand."
Now the reason of this seeming paradox is the basis of Mrs. Eddy's dictum about spiritual teaching. It is that mortal mind, or ignorance (not knowing), can no more enter into the kingdom of divine intelligence, into knowing God, than darkness can enter into light. So finite human sense can never understand infinity, but is destroyed by Truth. In Christian Science this destruction of the illusion of life in matter, whether expressed in sickness or health, is called healing, or God with us. Error is thus seen as illusion, and being thus destroyed, must disappear. Yet into the seeming darkness of unredeemed mortal thinking, Truth is forever flashing its rays, each a glimpse of divine intelligence, appearing in parable or symbol, to lead unto Christ.