"'You know how to interpret the appearance of the sky, but you cannot interpret the signs of the times. An evil and adulterous generation seeks for a sign, but no sign will be given to it except the sign of Jonah.'" Matthew 16:4
It has not been a good showing for the Pharisees, Saducees and the scribes in the Matthew 15 and 16. In chapter 15 some of them came from Jerusalem and took an offense at Jesus' disciples when the disciples did not wash their hands before eating. In return Jesus scolded them for keeping the traditions of men while they break the commandments of God. The example Jesus gives of this is that these men used the traditions of men as a means to dishonor their mother and father. This is somewhat scary because if these religious men will dishonor their mother and father then how much more harshly they will they treat someone who has no relationship to them?
Now in chapter 16 the Pharisees and the Sadducees came to test Jesus. They asked for Him to do a sign from heaven. Let me make a couple observations. First, in just a few verses Jesus compares the teaching of the Pharisees and the Sadducees to leven. Leven spreads quickly and infiltrates completely. Likewise, In chapter 15 these religious leaders came to him from Jerusalem. In chapter 16 there are new Pharisees and Sadducees approaching Christ with alterior motives. Leven does indeed spread great distances. It is in the hearts of all of these men from different places. The cultures we live in and associate with do indeed have a great impact upon us.
Secondly, notice that these are very religious men. They are the most well trained men of the day. And yet, they are also the ones that Jesus says, "Watch and beware of the leaven of the Pharisees and Sadducees." They are immersed in the religious institutions of their day, they are well educated, they are are the teachers of their day. Yet, despite all of this they are profoundly lost.
For example, in chapter 15 the traditions of men have priority over the Word of God. In chapter 16 these men are more informed about meteorology than they are in the true teachings of God. Jesus says, "When it is evening, you say, 'It will be fair weather, for te sky is red.' And in the morning, 'It will be stormy today, for the sky is red and threatening.' You know how to interpret the appearance of the sky, but you cannot interpret the signs of the times." As a result of all of this Jesus calls them a faithless, evil and an adulterous generation.
All of this reminds me of Psalm 19. In that psalm we see the proper way to see creation and also the importance of the Word in our lives. Creation gives glory to God and speaks of His handiwork. The one who can see this is farther along than these religious men. It also speaks of the perfection of the Law of the Lord and how it revives the soul.
A good way to approach the Word is found in Psalm 19:12-13, "Who can discern his errors? Declare me innocent from hidden faults. Keep back your servant also from presumptuous sins; let them not have dominion over me! Then I shall be blameless, and innocent of great transgression."
These religious men came to the Scriptures and used them to find fault with Jesus and His disciples; rather than, coming to them to have God reveal what they were blind too and to be forgiven. John Flavel once said, "God will allow His children to complain to Him, but not of Him." There is no fault in Him. There is no shadow in Him. There is only majestic glory.