In the first four verses of Matthew 16, we encounter a unique form of hypocrisy. Normally we think of this sin as teaching or claiming one thing in public, but then privately doing the opposite. But here Jesus critiques the Pharisees and Sadducees because of what they should see, but they cannot.
These two classes of religious leader did not like each other, and they had many differences. But they had this in common: they both wanted to see Jesus call down a sign from heaven (1). It seems that they really didn’t think he could; they wanted to expose him as a fraud.
But Jesus replies that they know how to interpret the signs in the sky, but they do not know how to interpret the sign that has already come down from heaven - that is, Jesus himself. They can tell when rain is coming, but they cannot tell when the long-promised, long-awaited manna from heaven has already come. They cannot see that the long-awaited season of the Messiah has come, and right before their eyes.
This is a unique form of hypocrisy. For on the outside, they pretend to want to see signs, but they are blind to it, and they will never see it. That is, as long as they continue in their “evil and adulterous” state (4). Sin blinds us. Thus until they repent, they will remain in their hypocritical blindness. This is why John came preaching a message of repentance, for only by repentance would the people make clear the way of the Lord, into their hearts.
And we may preach this too. It’s possible that people you know need to hear the message of repentance - that they will only be truly converted when they wipe the mud off the windshield of their souls, in order to see Christ most clearly.
So Jesus says, no sign will be given to a generation that will only interpret it and respond to it through the lens of their own lusts. Only one sign will be given: the sign of Jonah. Jonah spent three days and three nights in the belly of the whale, and it is my opinion that Jonah actually died inside the whale, only to be resurrected by God on the beach, just as Jesus would one day be raised.
It is not easy to understand the times one lives in. The key is to avoid simplistic categories and seeing everything through tribal loyalties. The first step is to realize that we live today under the reign of a risen King, ascended and sitting on His heavenly throne. He reigns, until God makes all his enemies his footstool (Psalm 110:1).