First, what is the Feast of Tabernacles? The Christianity section of About.com tells us that the Feast of Tabernacles is one of seven annual festivals of God that were presented to Israel during the Exodus. Dr. Towns cites it as “the greatest national feast of Israel.()” It is a pilgrimage festival, when the people journeyed from all over the nation to keep the Feast in Jerusalem. It lasts for eight days. On the final day, part of the ceremony was when a priest would take water from the pool of Siloam and pour it over the altar. Many people believe that this is why Jesus said in John 7:37(), “If any man is thirsty, let him come to Me and drink.” The Feast of Tabernacles also follows the Day of Atonement – the day when the High Priest entered the Holy of Holies with the sin offering. Jesus was referred to as a lamb by John the Baptist, “the lamb who takes away the sin of the world.” (John 1:29)(). His blood sacrifice would be poured on the alter and the temple veil would tear and annual offerings would no longer be needed. Another tradition was the lighting of the Temple lamps. Jesus states, “I am the light of the world; he that follow me shall not walk in darkness, but shall have the light of life.” (John 8:12). Morris states, “the demand for faith shows that it is not a question of physical illumination; Jesus is calling for faith in himself, and his use of “light” points to the illumination of life that he brings.()”
Christianity.About.com, http://christianity.about.com/od/biblefeastsandholidays/p/feastofbooths.htm (Accessed April 7, 2013) Elmer Towns, The Gospel of John: Believe and Live (Chattanooga: AMG Publishers, 2002), 76.  Holy Bible, John 7:37 (NIV)
 Holy Bible, John 8:12 (NIV)
 Leon Morris, Jesus Is the Christ: Studies in the Theology of John (Grand Rapids: William B Eerdmans Publishing Company, 1989), 113.