John Calvin on John 5:39

John 5:39 "You search the Scriptures because you think that in them you have eternal life; and it is they that bear witness about Me."

If we wish to obtain the knowledge of Christ, we must seek it from the Scriptures; for they who imagine whatever they choose concerning Christ will ultimately have nothing instead of him but a shadowy phantom. First, then, we ought to believe that Christ cannot be properly known in any other way than from the Scriptures; and if it be so, it follows that we ought to read the Scriptures with the express design of finding Christ in them. Whoever shall turn aside from this object, though he may weary himself throughout his whole life in learning, will never attain the knowledge of the truth; for what wisdom can we have without the wisdom of God? Next, as we are commanded to seek Christ in the Scriptures, so he declares in this passage that our labors shall not be fruitless; for the Father testifies in them concerning his Son in such a manner that He will manifest him to us beyond all doubt. But what hinders the greater part of men from profiting is, that they give to the subject nothing more than a superficial and cursory glance. Yet it requires the utmost attention, and, therefore, Christ enjoins us to search diligently for this hidden treasure. Consequently, the deep abhorrence of Christ which is entertained by the Jews, who have the Law constantly in their hands, must be imputed to their indolence. For the lustre of the glory of God shines brightly in Moses, but they choose to have a vail to obscure that lustre. By the Scriptures, it is well known, is here meant the Old Testament; for it was not in the Gospel that Christ first began to be manifested, but, having received testimony from the Law and the Prophets, he was openly exhibited in the Gospel.

-John Calvin on John 5:39