A voice in the wilderness: John, the baptism and the Son

The Gospel of Luke was written by Luke, the physician and companion of Paul (Colossians 4:14), according to early church tradition, and it is the first volume of a two-part work that continues in Acts. Some critical scholars question whether the author knew Paul, but few doubt that the author's name was Luke. The date is debated: an early date around the early 60s AD rests on the way Acts ends, while most critical scholars hold that Luke used Mark and wrote around AD 80 to 90. The synoptic problem, the question of how Matthew, Mark and Luke are related, is usually solved by Markan priority plus a shared sayings source, Q; others reject Q or defend Matthew's priority. Luke writes to Theophilus (1:3), mainly for Greek-speaking readers, to give an orderly account that confirms what they had been taught (1:4).

Luke 3 is where Luke picks up the thread he shares with Mark, who begins his Gospel here. Luke is the only Gospel writer to date the moment so exactly. The fifteenth year of Tiberius is most likely AD 28 or 29. Pontius Pilate governed Judea from AD 26 to 36 or 37. Herod Antipas ruled Galilee, his brother Philip ruled the territories east and north of the Sea of Galilee, and Lysanias is named as ruler of Abilene near Damascus. Annas had been high priest from AD 6 to 15 and was still influential, while his son-in-law Caiaphas held the office. By naming the powerful and then saying that the word of God came to a man in the wilderness, Luke sets the Gospel in world history and shows where God's attention fell.

John was the son of the priest Zechariah and Elizabeth (1:5-25, 57-80). The wilderness along the Jordan was the place where Israel had been formed, and the prophets looked for a return there (Hosea 2:14-15). The Jewish historian Josephus also mentions John and his baptism, and says Herod Antipas had him killed.

This chapter is historical narrative with prophetic preaching inside it. John's speech uses the rhetoric of Old Testament prophets: sharp images (a brood of vipers, an axe at the root, a winnowing fork), a call to repent, and the threat of judgment. The key is to hear it in a first-century Jewish setting. Baptism in water was already a washing for purification, and some groups practiced repeated immersions. John's baptism is once for all and tied to repentance and forgiveness, a public sign that even a Jew who already belonged to God's people was turning back to him.

Two literary choices matter.

• First, Luke finishes John's story before Jesus' baptism (3:19-20 tells of the imprisonment first, then 3:21 says Jesus was baptized). This is not a strict timeline, since John is still baptizing when Jesus comes. Luke gives John's work as a closed unit and moves the spotlight to Jesus.
• Second, Luke includes the genealogy after the baptism, so the voice of the Father ('You are My beloved Son') is followed directly by a list that ends 'the son of God'.

A hard question is the meaning of 'He will baptize you with the Holy Spirit and with fire' (3:16). The sentence is addressed to a mixed crowd. Verse 17 describes the coming One separating wheat from chaff, with the chaff burned in unquenchable fire, so many read 'fire' as the fire of judgment. Others read Spirit and fire together as a single cleansing and refining work, pointing to Pentecost (Acts 2:3). The class takes both as possible and reads the baptism as a single coming that brings blessing for some and judgment for others.

Verses 1–2

Luke names the emperor, the governor, three tetrarchs (rulers of a fourth part of a region) and two high priests. Then, in the plainest sentence of the chapter, the word of God came to John son of Zechariah in the wilderness. This is how the prophets are introduced (Jeremiah 1:1-2; Hosea 1:1). John is placed in their line.

Verses 3–6

John goes through the region around the Jordan preaching a baptism of repentance for the forgiveness of sins. 'Repentance' (metanoia) means a change of mind that leads to a change of life. Luke explains John with Isaiah 40:3-5: a voice crying in the wilderness to prepare the way for the Lord, with valleys filled and mountains made low. Luke is the only Gospel to quote on through verse 6, 'all humanity will see God's salvation', so the Gentile reach of his Gospel is announced here.

Verses 7–9

John speaks to the crowds coming to be baptized, and he does not flatter them. 'You brood of vipers, who warned you to flee from the coming wrath?' He demands fruit that fits repentance, and warns them not to rest on descent from Abraham, since God can raise up children for Abraham from stones. The axe is already lying at the root. Matthew 3:7 addresses the same words to Pharisees and Sadducees; Luke addresses all who came.

Verses 10–14

Three groups ask what they should do, and John gives concrete answers. The crowds are told to share a second tunic and food. Tax collectors, who worked for Roman contractors and were known for extortion, are told to collect no more than authorized. Soldiers are to avoid extortion and false accusation and be content with their wages. John does not tell them to leave their jobs; he tells them to practice justice and generosity within them. This material is only in Luke.

Verses 15–18

The people wonder whether John might be the Christ. John answers that he baptizes with water, but one more powerful is coming, whose sandal straps he is unworthy to untie, and who will baptize with the Holy Spirit and fire. The winnowing fork separates wheat from chaff on a threshing floor. Luke calls this preaching 'good news' (3:18), which shows how severe words and good news belong together in his view.

Verses 19–20

John rebukes Herod Antipas for taking his brother's wife Herodias and for other evils, and Herod shuts him in prison. Mark 6:17-29 and Matthew 14 tell the story of John's death in more detail.

Verses 21–22

Luke tells the baptism of Jesus in a single sentence, adding that Jesus was praying. Heaven opens, the Holy Spirit descends on him 'in a bodily form like a dove', and a voice says, 'You are My beloved Son; in You I am well pleased.' The detail of prayer is Luke's. The wording combines Psalm 2:7 (the king as God's son) with Isaiah 42:1 (the Spirit-anointed servant in whom God delights).

Verses 23–38

Jesus was about thirty years old when he began, and was regarded as the son of Joseph. The genealogy runs backward, through David and Abraham, all the way to 'Adam, the son of God'. Matthew's genealogy begins with Abraham and runs through Solomon; Luke's runs through David's son Nathan. Common explanations are that Matthew gives Joseph's legal line and Luke gives Mary's, with Heli as her father, or that levirate marriage explains the two lines for Joseph. Scholars have not reached agreement.

Luke 3 sets out the shape of the Gospel in a few lines. God speaks to his people by a prophet, calls for repentance, and promises both salvation and judgment through one who is coming. The doctrine of repentance here is tied to conduct. John's instruction to share, to be honest in business and to be fair in power shows that conversion in the Bible changes how people treat their neighbors. The claim that descent from Abraham does not save anticipates Paul's teaching that real children of Abraham are those of faith (Romans 4:11-12; Galatians 3:7).

The chapter also shows the Trinity in the baptism. The Son is baptized and is praying, the Spirit descends, and the Father speaks. Christians have read this as one of the clearest places where the three persons are distinguished in a single scene.

The genealogy anchors Jesus in the whole human story. Matthew traces him to Abraham, the father of the Jews. Luke traces him to Adam, the father of all humanity, and calls Adam the son of God. The implication, developed in Romans 5:12-19 and 1 Corinthians 15:45, is that Jesus is the new head of the race, who will succeed where the first son failed. The next chapter of Luke tests this immediately in the wilderness.

Luke 3 says who Jesus is in three ways. First, John is the fulfillment of Isaiah 40:3-5, the voice who prepares the way of the Lord. In Isaiah the Lord is the God of Israel coming to his people. Luke applies this to the coming of Jesus, and in Luke 1:76 John is already called prophet of the Most High who will go before the Lord. The Gospel thus ties Jesus to the identity of the LORD.

Second, the Father's words at the baptism name Jesus as the royal Son of Psalm 2:7 and as the servant of Isaiah 42:1 who receives the Spirit. These two Old Testament portraits, the conquering king and the humble servant, are joined in one person. Acts 10:38 says God anointed Jesus of Nazareth with the Holy Spirit and power. The baptism is the public beginning of that anointing.

Third, the genealogy makes Jesus the true Son in a line that failed. Adam was called to be God's son and fell; Israel was called God's son (Exodus 4:22) and failed in the wilderness. Jesus, whom the Father has just called his Son, is about to be led by the Spirit into that same testing, as the next chapter shows. The type is made explicit in Romans 5:14, where Adam is called a type of the one to come. John's own promise of the One who baptizes with the Spirit is fulfilled when Jesus pours out the Spirit after his ascension (Acts 2:33).