Three moments from The Hero with a Thousand Faces (1949), applicable not just to religion but also to literature and the arts.(There were two originally; I added a third a few hours later.)
Symbols are only the vehicles of communication; they must not be mistaken for the final term, the tenor, of their reference. No matter how attractive or impressive they may seem, they remain but convenient means, accommodated to the understanding. Hence the personality or personalities of God – whether represented in trinitarian, dualistic, or unitarian terms, in polytheistic, monotheistic, or henotheistic terms, pictorially or verbally, as documented fact or as apocalyptic vision – no one should attempt to read or interpret as the final thing. The problem of the theologian is to keep his symbol translucent, so that it may not block out the very light it is supposed to convey. “For then alone do we know God truly,” writes Saint Thomas Acquinas, “when we believe that He is far above all that man can possibly think or God.” And in the Kena Upanishad, in the same spirit: “To know is not to know; not to know is to know.” Mistaking a vehicle for its tenor may lead to the spilling not only of valueless ink, but of valuable blood. (236)
Wherever the poetry of myth is interpreted as biography, history, or science, it is killed.