From: Matthew 3:1-12
The Preaching of John the Baptist
 ln those days came John the Baptist, preaching in the wilderness of Judea, 2] "Repent, for the kingdom of heaven is at hand."  For this is he who was spoken of by the prophet Isaiah when he said, "The voice of one crying in the wilderness: Prepare the way of the Lord, make his paths straight."
 Now John wore a garment of camel's hair, and a leather girdle around his waist; and his food was locusts and wild honey.  Then went out to him Jerusalem and all Judea and all the region about the Jordan,  and they were baptized by him in the river Jordan, confessing their sins.
 But when he saw many of the Pharisees and Sadducees coming for baptism, he said to them, "You brood of vipers! Who warned you to flee from the wrath to come?  Bear fruit that befits repentance,  and do not presume to say to yourselves, 'We have Abraham as our father' ; for I tell you, God is able from these stones to raise up children to Abraham.'  Even now the axe is laid to the root of the trees; every tree therefore that does not bear good fruit is cut down and thrown into the fire.
 I baptize you with water for repentance, but he who is coming after me is mightier than I, whose sandals I am not worthy to carry; he will baptize you with the Holy Spirit and with fire.  His winnowing fork is in his hand, and he will clear his threshing floor and gather his wheat into the granary, but the chaff he will burn with unquenchable fire."
1. The expression "in those days" does not specify the exact time of the event in question. It is sometimes used merely as an opening phrase to mark the beginning of a new episode. In this case, in fact, it can be calculated that some twenty-five years have elapsed since the Holy Family's return from Egypt. This is only an estimate, because the exact date of their return has not been established.
On the date of the start of John the Baptist's preaching, see Luke 3:1-3. The word "wilderness" has a wider meaning here than we give it today. It does not refer to a sandy or rocky desert, but rather to arid regions, low in vegetation.
2. "Repent": Christ's redeeming work ushers in a new era in the Kingdom of God. This brings such advance in salvation history, that what is required from now on is a radical change in man's behavior towards God. The coming of the Kingdom means that God has intervened in a special way to save mankind, but it also implies that we must be open to God's grace and reform our ways. Christ's life on earth compels peopl e to take a stand--either for God or against him ("He who is not with me is against me, and he who does not gather with me scatters": Lk 11:23). Given man's sinful state after original sin, the newly-arrived Kingdom requires that all men repent of their past life. To put it another way, they have to stop going away from God and instead try to get closer to him. Since sin hinders this conversion, it is impossible to turn back to God without performing acts of penance. Conversion is not simply a question of making a good resolution to mend our ways; we have to fulfill that resolution, even if we find it difficult. Penance grows only where there is humility--and everyone should admit sincerely that he is a sinner (cf. 1 Jn 1 :8-10). Obedience also goes hand in hand with penance; everyone ought to obey God and keep his commandments (cf. 1 Jn 2:3-6).
The literal translation of the Greek is "Repent". But precisely because the very essence of conversion consists in doing penance, as we have said, the New Vulgate has "paenitentiam agite" ("do penance"). This translation conveys the deeper meaning of the text.
Man's whole life, in fact, consists in constantly correcting his behavior, and therefore implies a continual doing of penance. This turning back to God was preached continually by the prophets in the Old Testament. Now, however, with the coming of Christ, this penance and turning to God are absolutely essential. That Christ took on our sins and suffered for us does not excuse us from making a true conversion; on the contrary, it demands it of us (cf. Col 1:24).
"Kingdom of heaven": this expression is identical to "Kingdom of God". The former is the one most used by St Matthew, and is more in line with the Jewish turn of phrase. Out of reverence, the Jews avoided pronouncing the name of God and substituted other words for it, as in this case. "Kingdom of God" o r "Kingdom of heaven" was a concept used already in the Old Testament and in religious circles at the time of Christ. But it occurs particularly frequently in Jesus' preaching.
The phrase "Kingdom of God" can refer in a general way to God's dominion over creatures; but normally, as in this text, it refers to God's sovereign and merciful involvement in the life of his people. Man's rebellion and sin broke the order originally established in creation. To re-establish it, God's intervention was needed again; this consisted in the redeeming work of Christ, Messiah and Son of God. It was preceded by a series of preliminary stages in salvation history throughout the Old Testament.
Consequently, the Kingdom of God, announced as imminent by John the Baptist, is brought into being by Jesus. However, this is an entirely spiritual one and does not have the nationalistic dimension expected by Jesus' contemporaries. He comes to save his people and all mankind from the slavery of sin, from death and from the devil, thereby opening up the way of salvation.
In the period between the first and second comings of Christ, this Kingdom of God (or Kingdom of heaven) is, in fact, the Church. The Church makes Christ (and therefore also God) present among all peoples and calls them to eternal salvation. The Kingdom of God will be brought to completion only at the end of this world, that is, when our Lord comes to judge the living and the dead at the end of time. Then God will reign over the blessed in a perfect way.
In the passage we are considering, John the Baptist, the last of the Old Testament prophets, preaches the imminence of the Kingdom of God, ushered in by the coming of the Messiah.
3. By quoting Isaiah 40:3, St Matthew makes it clear that St John the Baptist has a mission as a prophet. This mission has two purposes--first, to prepare the people to receive the Kingdom of God; second, to testify before the people that Jesus is the Messiah who is bringing that Kingdom.
4. The Gospel gives a brief outline of the extremely austere life of St John the Baptist. His style of life is in line with that of certain Old Testament prophets and is particularly reminiscent of Elijah (cf. 2 Kings 1:8; 2:8-13ff.). The kind of food and dress described are of the most rudimentary for the region in question. The locust was a kind of grasshopper; the wild honey probably refers to substances excreted by certain local shrubs rather than to bees' honey. In view of the imminent coming of the Messiah, John underlines, with his example, the attitude of penance preceding great religious festivals (similarly, in its Advent liturgy the Church puts John before us as a model and invites us to practise mortification and penance). In this way, the point made in the previous verse (concerning John's view of his mission as precursor of Christ) is fulfilled. A Christian's entire life is a preparation for his meeting with Christ. Consequently, mortification and penance play a significant part in his life.
6. John's baptism did not have the power to cleanse the soul from sin as Christian Baptism does. The latter is a sacrament, a sign, which produces the grace it signifies. Concerning the value of John's baptism, see the note on Mt 3:11.
7. St John reproaches the Pharisees and Sadducees for their attitude towards him. His preaching and baptism are not simply one more purification rite. Rather, they demand a true interior conversion of the soul, as a necessary predisposition to reach the grace of faith in Jesus. In the light of this explanation, we can understand why the prophetic words of St John the Baptist were so hard-hitting; as it turned out, most of these people did not accept Jesus as the Messiah.
"Pharisees": these constituted the most important religious group in Jesus'' time. They kept the Law of Moses rigorously and also the oral traditions which had built up around it. They gave as much importance to these latter, indeed, as to the Law itself. They strongly opposed the influence of Greek paganism and totally rejected the homage paid to the Roman emperor. Among them there were men of great spiritual eminence and sincere piety; but there were many others who exaggerated pharisaical religiosity to the extreme of fanaticism, pride and hypocrisy. It was this perversion of the true Israelite religion that John the Baptist (and later our Lord) castigated.
"Sadducees": the Sadducees constituted a smaller religious group than the Pharisees, but they included many influential people, most of them from the main priestly families. They accepted the written Law, but, unlike the Pharisees, they rejected oral tradition. They also rejected certain important truths, such as the resurrection of the dead. On the political front, they went along easily with the terms dictated by the Romans, and they acquiesced in the introduction of pagan customs into the country .Their opposition to Christ was even more pronounced than that of the Pharisees.
9-10. St John the Baptist's listeners believe their salvation is assured because they are descendants of Abraham according to the flesh. But St John " warns them that to pass God's judgment it is not enough to belong to the chosen people; they must also yield the good fruit of a holy life. If they fail to do this, they will be thrown into the fire, that is, into hell, the eternal punishment, because they did not do penance for their sins. See the note on Mt 25:46.
11. St John the Baptist did not limit himself to preaching penance and repentance; he encouraged people to receive his baptism. This baptism was a way of interiorly preparing them and helping them to realize that the coming of Chris t was imminent. By his words of encouragement and by their humble recognition of their sins, they were prepared to receive Christ's grace through Baptism with fire and the Holy Spirit. To put it another way, John's baptism did not produce justification, whereas Christian Baptism is the sacrament of initiation which forgives sin and bestows sanctifying grace. The effectiveness of the sacrament of Christian Baptism is expressed in Catholic teaching when it says that the sacrament gives grace "ex opere operato". This means that grace is given by virtue of Christ who acts through the sacrament, and not by virtue of the merits of either the minister or the recipient of the sacrament. "When Peter baptizes, it is Christ who baptizes [...]. When Judas baptizes, it is Christ who baptizes" (St Augustine, "ln loann. Evang.", 6).
The word "fire" points in a metaphorical way to the effectiveness of the Holy Spirit's action in totally wiping out sins. It also shows the life-giving power of grace in the person baptized.
Foremost among the personal qualities of St John the Baptist is his remarkable humility; he resolutely rejects the temptation of accepting the dignity of Messiah which the crowds apparently wanted to bestow on him. Carrying the sandals of one's master was a job for the lowest of servants.
12. Verses 10 and 12 refer to judgment by the Messiah. This judgment has two parts: the first occurs throughout each man's life and ends in the Particular Judgment immediately after death; the second occurs at the time of the Last Judgment. Christ is the judge in both instances. Let us remember the words of St Peter in Acts 10:42: "And he commanded us to preach to the people, and to testify that he [Jesus] is the one ordained by God to be judge of the living and the dead." The judgment will give to each person the reward or punishment merited by his good or bad actions.
It is worth noting that the word "chaff" does not refer only to bad deeds; it refers also to useless ones, for example, lives lacking in service to God and men. God will judge us, therefore, for our omissions and our lost opportunities.
"Don't let your life be barren. Be useful. Make yourself felt. Shine forth with the torch of your faith and your love. With your apostolic life, wipe out the trail of filth and slime left by the unclean sowers of hatred. And set aflame all the ways of the earth with the fire of Christ that you bear in your heart" ([St] J. Escriva, "The Way", 1).
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.