The religious leaders of the day also arrived at the river’s edge and John pierced them with a steely gaze, pointed a bony finger at them, and declared: “‘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.’”
It was assumed that the religious leaders were already spiritual men, walking with God and living the life that went along with their pious declarations of being on the inside track with God.
John knew better than that. His own father had been part of the priestly class, and though Zachariah had been a righteous man, John would have grown up seeing that there were many whose pure robes covered impure lives. His remarks make us wonder if he held out any hope that their surface religiosity could ever be changed to true spirituality.
His challenge to the religious leaders was to prove their repentance through their acts—or else. The “or else,” described in verses 10 and 12 was a reminder that there would be a judgment day.
Once more we are reminded that this “good fruit,” this “fruit in keeping with repentance” is the evidence that a heart change has actually taken place. The fruit is an inevitable result of seed well-planted through repentance and confession of sins, and well-watered through the public commitment to follow the Lord demonstrated through baptism.