Writings and commentaries are chiefly available for the following purposes: to preserve, restore, or defend the purity of the text; to exhibit the exact force of the language employed by any sacred writer; to explain the circumstances under which any passage was uttered or written, or to which it refers; to remove errors or abuses which have arisen in later times.—The first hearers required none of these things. Now, however, it is the office of commentaries to effect and supply them in some measure,