Matthew doesn’t say what motivated the Pharisees and Sadducees to seek out John the Baptist. He only tells us what John said to them.

“You brood of vipers! Who warned you to flee from the coming wrath? Produce fruit in keeping with repentance. And do not think you can say to yourselves, ‘We have Abraham as our father.’ I tell you that out of these stones God can raise up children for Abraham. The ax is already at the root of the trees, and every tree that does not produce good fruit will be cut down and thrown into the fire.

Matthew 3:7b-10

Imagine a group of respected religious leaders going to hear a popular—and very peculiar—speaker, and he calls them a bunch of snakes and tells them that their actions need to reflect a change of heart. Not only that, he tells them something that is just short of blasphemy: that their ethnic identity as Jews is no guarantee of God’s favor. “You’re not special,” he tells them. Judgment is coming, and it will sweep away everyone whose deeds don’t measure up to what God demands.

Right away Matthew introduces an important theme in his account of Christ’s life. He tells us that the establishment with its privileges and power will face the same judgment as everyone else. No special status will be accorded to Israel’s leaders, whether their hope is in a miraculous deliverance (the Pharisees) or in appeasement of the civil authority (the Sadducees). The only hope is in a genuine repentance that presents itself in a changed life.