The story
From the Biblical accounts of John the Baptist, as in the Gospel of Mark, 1:2–4: "Behold, I send my messenger before thy face, which shall prepare thy way before thee. The voice of one crying in the wilderness, Prepare ye the way of the Lord, make his paths straight. John did baptize in the wilderness." (King James Version).
Etymology from Wiktionary, CC BY-SA 4.0.