We honor John the Baptist as a prophet sent “to prepare for the Lord a people well-disposed, to help God's people to walk the path of salvation.” The prophets were people who, like Isaiah, had God's words placed in their mouths. “They investigated the times,” and through their reading of the signs of the times, they were able to declare God's justice.
John the Baptist had the task of preparing the people immediately before the arrival of the messiah. His message was one of repentance, change of life, metanoia. His baptism was a sign of change, of turning things around, in the direction of God.
The lesson of John the Baptist is that the world will receive Jesus Christ when it turns away from its violent and oppressive ways. It must allow the prophets “to turn the hearts of fathers to their children and the rebellious to the wisdom of the just.”
In the face of the present-day situation of the world, marked as it is by the grave sin of injustice, we recognize both our responsibility and our inability to overcome it by our own strength. Such a situation urges us to listen with a humble and open heart to the word of God, as he shows us new paths towards action in the cause of justice in the world.
Synod of Bishops, Justice in the World, 1971:29