c. 391 · John Chrysostom, Homilies on the Gospel of John 41.1
Beloved, let us make great account of spiritual things, and not think that it is sufficient for us to salvation to pursue them anyhow. For if in things of this life a man can gain no great profit if he conduct them in an indifferent and chance way, much more will this be the case in spiritual things, since these require yet greater attention. Wherefore Christ when He referred the Jews to the Scriptures, sent them not to a mere reading, but a careful and considerate search; for He said not, “Read the Scriptures,” but, “Search the Scriptures.” Since the sayings relating to Him required great attention, (for they had been concealed from the beginning for the advantage of the men of that time,) He biddeth them now dig down with care that they might be able to discover what lay in the depth below. These sayings were not on the surface, nor were they cast forth to open view, but lay like some treasure hidden very deep. Now he that searcheth for hidden things, except he seek them with care and toil, will never find the object of his search.