One Bible commentary* I read described the context of Jesus’ declaration the He was “the light of the world.” On the evening of the first night of the Feast of Booths, there was a ceremony called the “Illumination of the Temple,” which involved the ritual lighting of four golden candelabra in the Court of Women. For additional reflection, each person lit four candlesticks and set them in a floating bowl, producing such a spectacle of light that it is said that all Jerusalem glowed. All night long the light shone. In celebration and anticipation, Israel’s men danced before the Lord and sang psalms of joy and praise, while the people watched and waited. They watched and waited, because this festival reminded the citizens of Israel that God had promised to send a light, the Light, to a sin-darkened world. God had promised to send a Redeemer, the Anointed One, the Messiah, the Son of God. God had promised to send Someone who would renew Israel’s glory, release them from bondage, and restore their joy. The setting of John 12 is the Temple, the Court of Women, on the last day of the Feast of Booths. The candles have been lit and the people have again been reminded of the Messiah’s coming. In this setting Jesus makes a dramatic announcement: “I am the light of the world.” Everyone knew what He meant. Jesus is saying: “What you’ve been watching and waiting and hoping for in the Feast of Booths is now before you. I am the light God has promised you.”

* http://www.oneyearbibleblog.com/