LAMB OF GOD
A phrase used by John the Baptist to describe Jesus <John 1:29,36>. John publicly identified Jesus as "the Lamb of God who takes away the sin of the world!" Elsewhere in the New Testament Jesus is called a lamb <Acts 8:32; 1 Pet. 1:19; Rev. 5:6>. The Book of Revelation speaks of Jesus as a lamb 28 times.
John's reference to Jesus as the Lamb of God calls to mind the Old Testament sacrifical system. In the sacrifice God accepted the blood of animals as the means of atonement for sin. It is likely that John had many themes from the Old Testament in mind when he called Jesus the Lamb of God. These themes probably included the sin offering <Leviticus 4>, the trespass offering <Leviticus 5>, the sacrifice on the Day of Atonement <Leviticus 16>, and the Passover sacrifice <Exodus 12>.
(from Nelson's Illustrated Bible Dictionary)
(Copyright (C) 1986, Thomas Nelson Publishers)