Commentators stress the vital distinction made in this verse. John the Baptist was a powerful prophet, a "burning and shining light" (Source 8), but he was not the ultimate source of light. His role was like that of the moon, reflecting the sun's glory. The Gospel writer makes this clarification because many people at the time wondered if John himself was the Messiah (Source 3). John's greatness lay in pointing away from himself to Jesus, the true Light.