Albert Barnes Commentary John 3:12

"If I told you earthly things and ye believe not, how shall ye believe if I tell you heavenly things?" — John 3:12 (ASV)

If I have told you earthly things. Things which occur on earth. Not sensual or worldly things, for Jesus had said nothing of these; but he had told him of operations of the Spirit which had occurred on earth, whose effects were visible, and which might be, therefore, believed. These were the plainest and most obvious of the doctrines of religion.

How shall you believe. How will you believe. Is there any probability that you will understand them?

Heavenly things. Things pertaining to the government of God and his doings in the heavens; things which are removed from human view, and which cannot be subjected to human sight; the more profound and inscrutable things pertaining to the redemption of men. Learn from this:

1. The height and depth of the doctrines of religion. There is much that we cannot yet understand.

2. The feebleness of our understandings and the corruptions of our hearts are the real causes why doctrines of religion are so little understood by us.

3. There is before us a vast eternity, and there are profound wonders of God's government, to be the study of the righteous, and to be seen and admired by them for ever and ever.