Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me (John 5:39).
From my reading of the text, Jesus disapproves of searching the scriptures while he addresses “the Jews” (John 5:18) who question him. The reason for this in this particular passage suggests that his hearers relied too much on the written word instead of accepting the living voice of John the Baptist. His tone is suggestive and not commanding, therefore Jesus did not instruct his readers to search the scriptures, rather he criticized them openly for searching but not understanding their sacred texts.
One commentator wrote:
Search the scriptures – The word translated “search” here (ἐραυνάω) means to “search diligently” or “search anxiously.” It was applied to miners, who search for precious metals – who look anxiously for the “bed” of the ore with an intensity or anxiety proportionate to “their sense” of the value of the metal. It is applied by Homer to a lioness robbed of her whelps, and who “searches” the plain to “trace out” the footsteps of the man who has robbed her. It is also applied by him to dogs tracing their game by searching them out by the scent of the foot. It means a diligent, faithful, anxious investigation The word may be either in the indicative or imperative mood. In our translation it is in the imperative, as if Jesus commanded them to search the Scriptures. Cyril, Erasmus, Beza, Bengel, Kuinoel, Tholuck, DeWette, and others, give it as in the indicative: Chrysostom, Augustine, Luther, Calvin, Wetstein, Stier, Alford, and others, regard it as in the imperative, or as a command. It is impossible to determine which is the true interpretation. Either of them makes good sense, and it is proper to use the passage in either signification. There is abundant evidence that the Jews did search the books of the Old Testament. It is equally clear that all people ought to do it. 1