If I have told you earthly things, and you believe not, how shall you believe, if I tell you of heavenly things?
All Commentaries on John 3:12 Go To John 3
Cornelius a Lapide
If I have told you earthly things, &c. "If thou understandest not Divine things by means of the earthly similitudes of human generation of flesh and spirit, how wilt thou understand them, if I were to set them before thee without any figures? For this I might do, since I have seen them as they are in themselves, and beheld them with the eyes of the mind. But thine eyes would be blinded by such light as that, and couldst not look upon it. Wherefore I advise thee not to dispute with Me about them, but to believe them by simple faith."
S. Chrysostom explains somewhat differently: thus, "earthly things" refer to earthly baptism, or that which is done on earth, or that which, in comparison with His own ineffable generation, He calls such. It means, If you do not understand My earthly baptism, how will you understand the Divine mysteries of the Holy Trinity, the eternal generation of the Word, the procession of the Holy Ghost? Do not therefore curiously inquire into those things, or dispute with Me about them, but simply believe Me, who Amos , as it were, a Divine Witness.