The parallel accounts are found at Mark 1:2-8; Luke 3:3-17; John 1:19-27. They ought be read. Also, Isaiah 40 ought be read in its entirety. The parallel texts can be studied from Exegetical Notes on Advent II and Advent III Series C.
"In those days" simply points to the time when John was preaching but Jesus had not yet entered His public office. Note how the Gospel of John distinguishes the two. Compare John 1:19-27 with 1:28-34. Jesus had not yet appeared in His public office. John heralded, merely repeating what his King (God) had told him to say.
Compare the first of Luther's 95 Theses.
In classical Greek the word "repent" means "think ahead" (so that you have no regrets) and "have afterthoughts" (denoting no regret because of lack of careful forethought). Lenski rightly says it means "to perceive or see afterward; i.e. when it is too late." But he should have added that the great difference between classical and New Testament Greek with regard to this word is that "what is too late" for the unregenerate Greek is the very beginning for the Christian.
Here "repent" is used in the wider sense: "be contrite and believe."
"For" gives the reason. "There has drawn near the Kingdom of heaven." Jesus Christ is about to appear. He brings the Kingdom of heaven.
The Kingdom belongs to heaven, and it also leads to heaven.
This is an explanation of the part played by the Baptist. God is the agent. The prophet Isaiah was only the mouthpiece of God.
The second and third lines of the prophecy are Hebrew parallelism, saying the same thing in different words. In prophecy they say precisely what the Baptist said in verse 2.
By the way, when Jesus came on the scene, 4:17, He said precisely the same thing as did the Baptist. Even the same verbs are used as in 3:1. Their message was the same: acknowledge your sin, confess it, believe in the Messiah for forgiveness, abandon your sins, do works in keeping with your repentance.
Three articles are mentioned: robe, belt and food. It reminds one of 1 Timothy 3:3: "not a money-lover." Also of 1 Timothy 6:6-10.
A model for those who heard him. It takes very little in this life for the one who truly trust his Lord. The Baptist practiced what he preached. This verse proves it.
By the way, Luther has a beautiful passage in the Smalcald Articles on this passage:
Luther: Here the fiery angel St. John, the preacher of true repentance, intervenes. With a single thunderbolt he strikes and destroys both (the scribe and the Pharisees). 'Repent' he says. On the one hand there are some who think, 'We have already done penance' and on the other hand there are others who suppose 'We need no repentance.' But John says 'Repent, both of you. Those of you in the former group are false penitents, and those of you in the latter are false saints. Both of you need the forgiveness of sins, for neither of you knows what sin really is, to say nothing of repenting and shunning sin. None of you is good. All of you are full of unbelief, blindness, and ignorance of God and God's will. For He is here present, and from His fullness have we all received, grace upon grace, John 1:16. No man can be just before God without him. Accordingly, if you would repent, repent rightly. You repentance accomplishes nothing. And you hypocrites who think you do not need to repent, you brood of vipers, who has given you any assurance that you will escape the wrath to come?'
People in verses 5-6 did listen. Those in verses 7-12 evidently did not. In which group are we?
Notice that the verbs in 5 and 6 are imperfect of continued action. From these verses it has been estimated that from 200,000 to 500,000 people were baptized by John. John's disciples, so far as we can tell, did not baptize. Only John did that.
Notice the extent of the visitation of people: Jerusalem, Judea, all of it, and all the country surrounding the Jordan River. Look at Matthew 11:12 or Luke 16:16. Hordes came into the Kingdom of God through the Baptist. The text does not say that they came to be baptized. It simply says "they were baptized."
This denotes their contrition over sin.
No passage in the New Testament can be used to support immersion baptism. The Greek word "to baptize" simply means to apply water.
This is a new paragraph. A change of subject.
It is said of neither those in 5-6 nor of those in 7-12 that they came to be baptized. We think that the sole difference was that the former truly listened to what he said,and then confessed their sins and were baptized, but that the latter did not confess their sins. By the LACK of their confession John could tell that they remained impenitent. If that is not so, he would have had to look into their hearts. No indication of that.
Lenski thinks that they came to be baptized because so many others came and that the Pharisees and Sadducees did not want to lose their control over them. Maybe. Furthermore, he thinks that the delegations mentioned at John 1:19-27 must have followed later than the account in Matthew 3:1-12. That may be too. But all we wish to point out is that the text does not say that they came to be baptized.
Furthermore, confession of sins is conspicuous by its absence. The Pharisees were known for their legalism and self-righteousness. The Sadducees were know for their skepticism and moral laxness, the modern antinomians and "situation ethics" people. Neither confessed their sins. That is crystal clear from the context. No wonder John called them "Products of deadly snakes." They were like their forebears, deadly to self and others because of their self-sufficiency.
Read Luther again, quoted above. In the quotation above, Luther brings out the meaning of the rhetorical question very well: "Who has given you any assurance that you will escape the wrath to come?" The answer is easy: "No one has." The coming wrath is eschatological but not limited to that. That becomes clear in the following verse.
"In view of the fact that no one has assured you." Verses 8-12 are full of metaphors. Dead trees produce no fruit. Living trees do. What makes a person alive? Repentance. Here we quote Apology, Art. XII, par. 28:
Apology: In order to deliver pious consciences from these labyrinths of the scholastics, we have given repentance two parts, namely, contrition and faith. If someone wants to call fruits worthy of repentance, Matthew 3:8, and an improvement of the whole life character a third part, we shall not object.
In other words, the word "repentance" is used in the wider sense. If there is not contrition and faith, there will be no fruit, newness of life. Evidently the Pharisees and Sadducees did not confess sins nor accept his Gospel. John could easily determine that.
In verse 8 a command. In verse 9 a prohibition. "Don't ever get the idea to say (privately) to yourselves." From John 8:37-59 we know that Jesus knew how His enemies reasoned. Somehow the Baptist knew that too.
The people thought that mere physical decent was enough. Furthermore, they considered all Gentiles, those not descended from Abraham, lost. (Do we secretly think that our family is better simply by mere physical descent?)
"I tell you" is used by Christ and His appointed prophets as the voice of authority.
What does John mean? "Children to Abraham" means "children of God, believers." "To raise up" implies deadness. He is speaking of a miracle which only God can perform. They predicated membership in the Kingdom on mere physical descent. John says: "Don't ever get that idea!" And implicit in this statement is the idea that those not descended from Abraham, the Gentiles, God can raise up, despite their total lack of life. It's a straightforward word of warning and Law.
The Pharisees and Sadducees did not confess their sins. Therefore, John preaches only Law, in verses 7-10, to them. No Gospel for impenitent sinners.
"Already now" is prominent. The metaphor of the tree is continued. The axe already lies right at the root of the trees, Not fruit, limbs or trunk which are dead, but the very root. Total cutting off is imminent. The wrath of God abides on him who rejects Christ.
"Every tree." God's justice is precise. Note the repetition of words used in verse 8. John is speaking of the person who is devoid of repentance.
The last words denotes its total uselessness. Look at John 3:19-20. The works of the impenitent person are evil and useless. He hates Jesus, the Light, and refuses to come to Him, lest his works be made evident.
In verses 11-12 John compares himself with Jesus. These verses need the most careful exegesis.
John compares "I, for my part" and "but He."
"Repentance" here does not mean that contrition and faith only follow Baptism. Some of the translations make this verse sound like baptism is only proof , not a means of grace.
"For repentance" occurs nowhere else in the New Testament with reference to "baptism." John is here talking to impenitent Pharisees and Sadducees.
Lenski: 'For repentance' refers to the repentance manifested by all those who came to be baptized by John.
In verse 6 those baptized were confessing their sins. This is not said of those in verses 7-10 and John is plainly telling them that they are not repenting
We suggest that the phrase "for repentance" means a baptism involving repentance and leading to the proper resultant repentant living. John is NOT saying that his baptism is a mere form, devoid of the Holy Spirit. "For repentance" clearly denotes the spiritual power of John's baptism.
The one coming is Jesus. He is stronger, which implies that John is strong. "Of whom I am not worthy to bear His sandals" pictures John as servant.
"Will baptize" should not be limited to Pentecost.
John is not talking about a different baptism, because John 4:2 tells us that Jesus baptized no one. It means that in baptism, whether by John or by Jesus' disciples, Jesus bestowed the Holy Spirit and His cleansing power. Look carefully at John 1:33 "the One Who IS baptizing with the Holy Spirit." Some translations mistakenly translate this with the future. Wrong. In John 1:29-34 the Baptist is saying that in John's baptism, limited to Israel, Jesus IS baptizing with the Holy Spirit.
This Holy Spirit cleanses the baptized person. In Titus 3:5 baptism is called "the washing of regeneration and renewing of the Holy Spirit." And Paul says in Ephesians 4:5 that there is ONE baptism, not two. The Baptist's baptism was limited to Israel, looked forward to the fulfillment of the promises BUT IT WAS THOROUGHLY CHRISTIAN.
Likewise that of Jesus' disciples before Pentecost, John 4:1. Beginning with Pentecost, when all the promises had been fulfilled, baptism was FOR ALL NATIONS, likewise thoroughly Christian.
Christ bestowed the Holy Spirit and His cleansing work in the Baptist's baptism and all others thereafter. Never depart from that.
By the way, did these Pharisees and Sadducees repent and undergo baptism? Likely not. Look at Luke 7:30 and 20:3-8.
A beautiful metaphor, the threshing floor. With finality grain and chaff are separated when they are thrown up for the wind to drive the chaff away, never to be joined again. A stern warning: "If you reject this Christian baptism in impenitence you must face Christ as Judge." Look at John 3:36.