Just as God can be known only through his own revelation, so too humanity – the real truth about humanity – may be known only through the revelation of God. In this regard, the reader may be familiar with Calvin’s famous assertion:
“…it is evident that man can never attain to a true knowledge of self until he have previously contemplated the face of God, and come down after such contemplation to look into himself.”
– John Calvin (1509-1564), Institutes of the Christian Religion, I.i.2.
A few decades before Calvin’s final edition of the Institutes (1559), a Reformer in Zurich on the other side of Switzerland from Calvin’s Geneva, namely Huldrych Zwingli (1484-1531), wrote something similar:
“To know man is as toilsome as to catch a cuttlefish, for as the latter hides himself in his own blackness in order not to be caught, so does man, as soon as he sees one is after him, stir up such sudden and thick clouds of hypocrisy that no Lynceus, no Argus, can discover him. Not only that biting critic Momus complained of this, but the divine herald of the Gospel, Paul, understood it so well that in 1 Cor. 2:11 he speaks on this wise: ‘For who among men knoweth the things of a man, save the spirit of the man, which is in him?’ Though he says this only for the purpose of illustration, he really holds it as established that the human heart hides its purposes with such zeal and so many wiles that no one can have knowledge of them but itself; for unless this were his view, he could not logically draw the conclusion he is trying to prove in the passage. And Jeremiah says of this fleer from the light and this wiggler of ours, chap. 17:0, ‘The heart of man is wicked and unsearchable. Who can know it? I, the Lord, who search the heart and try the reins,’
From this testimony it becomes manifest that man cannot be known by man.”
– Huldrych Zwingli (1484-1531), Commentary on True and False Religion, Works 3:75-76