48.Whence knowest thou? Though Christ did not intend to flatter him, yet he wished to be heard by him, in order to draw forth a new question, by the reply to which he would prove himself to be the Son of God. Nor is it without a good reason that Nathanael asks whence Christ knew him; for to meet with a man of such uprightness as to be free from all deceit is an uncommon case, and to know such purity of heart belongs to God alone. The reply of Christ, however, appears to be inappropriate; for though he saw Nathanael under the fig-tree, it does not follow from this that he could penetrate into the deep secrets of the heart. But there is another reason; for as it belongs to God to know men when they are not seen, so also does it belong to Him to see what is not visible to the eyes. As Nathanael knew that Christ did not see him after the manner of men, but by a look truly divine, this might lead him to conclude that Christ did not now speak as a man. The proof, therefore, is taken from things which are of the same class; for not less does it belong to God to see what lies beyond our view than to judge concerning purity of heart. We ought also to gather from this passage a useful doctrine, that when we are not thinking of Christ, we are observed by him; and it is necessary that it should be so, that he may bring us back, when we have wandered from the right path.