Jesus Christ is the Lamb of God. He is the sacrificial lamb, offered by God to atone for the sins of man.
Isaiah 53:7
He was oppressed and afflicted, yet he did not open his mouth; he was led like a lamb to the slaughter ... (NIV)
John 1:29
The next day John saw Jesus coming toward him and said, "Look, the Lamb of God, who takes away the sin of the world!" (NIV)
Revelation 7:10
And they cried out in a loud voice: "Salvation belongs to our God, who sits on the throne, and to the Lamb." (NIV)