Each new generation needs to take stock afresh of this sacred legacy, so that it may obtain from ancient learning, study and inspiration the true message for its own times. The tares must be gathered out from the wheat, and the chaff separated from the grain. Truth, too, constantly needs re-statement; language and ideas are always changing; words and phrases do not convey to us the same meaning as they did to our grandfathers. Religious teaching deals largely in metaphors, and a metaphor may be a guiding light to one generation, and a will-o'-the-wisp to the next. As times change, aspects of the truth once prominent may be passed over lightly, and new views of the same truth must be emphasized to suit the needs of a new dispensation. The church in its age-long pilgrimage ever attains new heights from which it beholds a wider range of the vast expanse of sacred truth; for the most part it is the same landscape which was seen of old; but something is lost to sight, some tracts which once filled the field of vision have become dim and small; new glories are revealed, and the true relations of mountain, valley, and plain, of river, lake, and sea are discerned as they never were before. Commentators and expositors have not merely to repeat the shibboleths of forgotten controversies, they have the more onerous task of making the new view of the Heavenly Vision an intelligible, living, speaking picture for the men and women of their day. At the time when the publication of this series began there was urgent need for a new exposition of the Old Testament. The nineteenth century had obtained wonderful results from research in science and history, and from the progress of thought in philosophy, criticism, and theology; men were dazzled with new facts and new ideas. How were they to understand the Bible in the light--one might almost say in the glare--of this new truth? The scientific researches associated with the names of Wallace and Darwin, and with the term Evolution, have altogether changed our ideas of Nature and man, and of their relation to each other. Our knowledge of the history of the race is fuller and deeper than it was, and goes back to a far more remote antiquity. Democracy both as an idea and as a practical system is affecting thought, feeling, and character as it never did before, both for good and evil. This latter feature is perhaps one cause of the modern tenderness towards acute physical pain, and this tenderness, again, has done much to modify the sterner doctrines of the old theology. In many other ways too theology has become, as some would say, more vague; or, as others would prefer to put it, more elastic and better able to adapt itself to the varied circumstances of life.