“Truly, truly, I say to you, we speak of what we know, and bear witness to what we have seen, but you do not receive our testimony. If I have told you earthly things and you do not believe, how can you believe if I tell you heavenly things?” (John 3:11–12, ESV)
Oh if only Jesus would have explained himself when he said things like the above passage. Whatever can he mean when he contrasts earthly things with heavenly things? We have to put on our thinking caps here because other passages in which the same expression is used help us to understand the meaning of the words, but not explain what Jesus meant. In other words, we do understand that Jesus meant earthly things and heavenly things, but what earthly things? What heavenly things? Does he mean temporal things contrasted with eternal things? As if he were instructing them on how to properly grow crops, but they just weren’t getting it! They can’t figure out how to make proper mutton, how is he going to explain eternity?
We can begin to understand what Jesus meant when we consider the difference between Matthew, Mark, and Luke, compared with the Gospel of John. The prior recount mainly Christ’s instruction about earthly things and their relationship to God and his kingdom. For instance, consider this passage:
“And which of you by being anxious can add a single hour to his span of life? And why are you anxious about clothing? Consider the lilies of the field, how they grow: they neither toil nor spin, yet I tell you, even Solomon in all his glory was not arrayed like one of these. But if God so clothes the grass of the field, which today is alive and tomorrow is thrown into the oven, will he not much more clothe you, O you of little faith?” (Matthew 6:27–30, ESV)
Jesus is instructing his listeners in regards to being anxious on earth and how they might gain confidence from their understanding of how God constructs lilies and clothes the grass of the field. He is drawing their attention to earthly things and then instructing them on how God interacts with those things in order to teach them a lesson. These are the earthly things of John 3.12. God in relation to things on earth.
When one gets to being “born again” and “eternal life” (vs. 15), one is on a whole new level of things. These are heavenly things that require a much different framework to understand. It is these things with which the Gospel of John is chiefly concerned. Here is how one commentator (Vincent) explains it:
The author of the fourth Gospel was then clearly aware of two ways of teaching adopted by Jesus; the one the usual, in which he explained earthly things, evidently always in their relation to God and His kingdom; the other, which contrasted in many respects with the first, and which Jesus employed only exceptionally, in which He spoke directly, and as a witness, of God and the things of God, always naturally in connection with the fate of mankind.
To explain it further (Vincent):
Not holy things as compared with sinful, nor spiritual things as compared with temporal; but things which are in heaven, mysteries of redemption, having their seat in the divine will, realized in the world through the work and death of Jesus Christ and the faith of mankind (v. 14–16).
In other words, if Nicodemus and his peers couldn’t understand Jesus when he explained to them how they didn’t need to worry about “stuff” because God takes care of even the smallest matters, then they certainly were not going to understand when he started explaining to them that they must be born again. This was a radical new thing that required spiritual comprehension to understand, and of course most of the Jewish leaders were spiritually blind.
pair of multitude of readers, both things are important; God and how he interacts with our daily lives and decisions, and the spiritual doctrines that lead one to eternal life; but the heavenly things are harder to understand.