When 40 days old, Jesus was brought to the temple. At that time, the Holy Ghost was upon a man named Simeon who upon seeing the baby said:

Lord, now lettest thou thy servant depart in peace, according to thy word: For mine eyes have seen thy salvation, Which thou hast prepared before the face of all people; A light to lighten the Gentiles, and the glory of thy people Israel. Luke 2:29-32

Even at only 40 days old, Jesus was recognized as being the light of the world.