John the Baptist saw Jesus coming toward him and said,
“Behold, the Lamb of God, who takes away the sin of the world.
He is the one of whom I said,
‘A man is coming after me who ranks ahead of me
because he existed before me.’
I did not know him,
but the reason why I came baptizing with water
was that he might be made known to Israel.”
John testified further, saying,
“I saw the Spirit come down like a dove from the sky
and remain upon him.
I did not know him,
but the one who sent me to baptize with water told me,
‘On whomever you see the Spirit come down and remain,
he is the one who will baptize with the Holy Spirit.’
Now I have seen and testified that he is the Son of God.”
1:29 The Lamb of God: the background for this title may be the victorious apocalyptic lamb who would destroy evil in the world (Rev 5–7; 17:14); the paschal lamb, whose blood saved Israel (Ex 12); and/or the suffering servant led like a lamb to the slaughter as a sin-offering (Is 53:7, 10).
1:30 He existed before me: possibly as Elijah (to come, Jn 1:27); for the evangelist and his audience, Jesus’ preexistence would be implied (see note on Jn 1:1).
1:31 I did not know him: this gospel shows no knowledge of the tradition (Lk 1) about the kinship of Jesus and John the Baptist. The reason why I came baptizing with water: in this gospel, John’s baptism is not connected with forgiveness of sins; its purpose is revelatory, that Jesus may be made known to Israel.
1:32 Like a dove: a symbol of the new creation (Gn 8:8) or the community of Israel (Hos 11:11). Remain: the first use of a favorite verb in John, emphasizing the permanency of the relationship between Father and Son (as here) and between the Son and the Christian. Jesus is the permanent bearer of the Spirit.
1:34 The Son of God: this reading is supported by good Greek manuscripts, including the Chester Beatty and Bodmer Papyri and the Vatican Codex, but is suspect because it harmonizes this passage with the synoptic version: “This is my beloved Son” (Mt 3:17; Mk 1:11; Lk 3:22). The poorly attested alternate reading, “God’s chosen One,” is probably a reference to the Servant of Yahweh (Is 42:1).
Friends, our Gospel for today contains one of the most important and misunderstood lines in all of Christian Scriptures. Spying Jesus, John the Baptist says, “Behold the Lamb of God.” In a very casual survey, I asked a number of people what this phrase means, and the answer I typically got was this: it means that he is gentle and humble and good, like a lamb.
But for a first century Jew, the phrase had little if anything to do with that: it had to do with sacrifice. It meant that Jesus was someone who was destined to be sacrificed as a sin offering to God.
John the Baptist’s characterization of Jesus as the Lamb of God has to do with temple sacrifice. He will be the one who offers the final and definitive sacrifice which reconciles divinity and humanity. He will offer something to the Father which will deal finally with the problem of sin, and in this we will find our salvation.
– Bishop Robert Barron
May the virtues of faith, hope, and love go with you today – DV.
 Donald Senior, John J. Collins, and Mary Ann Getty, eds., The Catholic Study Bible, 2nd Ed.: Notes, 2nd ed., vol. 2 (New York: Oxford University Press, 2011), 1489.