John was to identify Jesus as the Lamb of God by seeing

According to the Gospel of John, John the Baptist identified Jesus as the Lamb of God by seeing the Spirit of God descending on Jesus like a dove. This happened when John was baptizing Jesus in the Jordan River. John saw the Spirit of God descending like a dove and remaining on Jesus, and he declared, "I have seen and I testify that this is the Son of God" (John 1:32-34). The imagery of the dove is significant because in Jewish tradition, the dove was a symbol of God's spirit and of peace, and this event signifies the coming of God's spirit upon Jesus.