John the Baptist prepared the way for the coming of Jesus by preaching in the wilderness of Judea (Judges 1:16, Psalm 63:1), but his very short ministry had influence even beyond the earliest Christian congregations (see Acts 18:25 and Acts 19:1–7). He was clear that he was only the herald for the Messiah. His preaching in the wilderness was an implicit condemnation of the superficial religion of Jerusalem.
He preached in the wilderness of Judea (Judges 1:16, Psalm 63:1), in other words, in the wilderness between the Judean mountains and the Dead Sea. His ministry was exceptionally short, but his influence was very great, stretching even beyond the earliest Christian congregations (see Acts 18:25 and Acts 19:1–7).1
John the Baptist (the recognized prophet) appeared in the period in which God caused his Son to be born of Mary and to grow up in Galilee. Many Jews at the time actually considered John the Baptist to be more important than Jesus. This is why Matthew begins Jesus’ story by referring to John the Baptist, thereby clarifying to the Jews that John the Baptist is not the most important, but that Jesus is.2 It is significant that he preaches publicly, as this shows that the gospel is no secret doctrine but a call to each and everyone.
Preaching in the wilderness was also highly symbolic. Very little true religion was found in Jerusalem in those days. The leaders of the people were unfaithful and often completely godless. The temple service was not conducted in accordance with his commands and God no longer spoke to the people through the priests. Israel had to return to the wilderness with its rough and deserted character which served to remind Israel of her spiritual condition and need for repentance.3
1 En ce temps-là parut Jean-Baptiste, prêchant dans le désert de Judée.