29 The next day he saw Jesus coming to him and said, "Look! The Lamb of God 1:29 John is referring to the fulfillment of the need for the OT Passover lambs which was now fulfilled in Christ’s sacrifice, the ultimate and final sacrifice for sins.who takes away the sin of the world! [Ex 12:3; Is 53:7] 34 I myself have [actually] seen [that happen], and my testimony is that this is the Son of God!"