The next day John saw Jesus coming toward him, and said, "Behold! The Lamb of God who takes away the sin of the world!
John 1:29
Surrounding context
1:28 These things were done in Bethabara beyond the Jordan, where John was baptizing.
1:29 The next day John saw Jesus coming toward him, and said, "Behold! The Lamb of God who takes away the sin of the world!
1:30 This is He of whom I said, "After me comes a Man who is preferred before me, for He was before me.'