Alpha and Omega are the first and last letters of the Greek alphabet. In Christianity, this pair of letters is used as a symbol and often combined with the Cross, Chi-rho, or other Christian symbols. The phrase "I am the Alpha and the Omega" is an appellation of Jesus and of the Father in the Book of Revelation. The phrase is interpreted by many Christians to mean that Jesus has existed for all eternity or that God is eternal. The phrase "Alpha and Omega" is used to designate the comprehensiveness of God, implying that Jehovah alone is the beginning and the end. The phrase "Alpha and Omega" is also used to refer to the basic or essential element or elements.

In summary, Alpha and Omega are the first and last letters of the Greek alphabet and are used as a symbol in Christianity. The phrase "I am the Alpha and the Omega" is an appellation of Jesus and of the Father in the Book of Revelation and is interpreted by many Christians to mean that Jesus has existed for all eternity or that God is eternal. The phrase "Alpha and Omega" is also used to refer to the comprehensiveness of God and the basic or essential element or elements.