AS WE’VE SEEN, chapter 1 of Luke’s gospel ends with John in the wilderness; chapter 2 then turns to stories surrounding Jesus’ birth and boyhood. At the beginning of chapter 3, Luke swings back to pick up John’s story where it left off, in the wilderness; that’s where his public ministry begins. Then, after reporting John’s imprisonment by Herod Antipas, Luke turns the spotlight back to Jesus, beginning with the story of his baptism. Obviously, Luke is not narrating the events of chapter 3 in strictly chronological order, since John baptized Jesus before Herod locked him up. Moreover, because Luke is now focusing again on Jesus, he doesn’t even mention John’s name when describing the baptism. Here’s what he says:

When all the people were being baptized, Jesus was baptized too. And as he was praying, heaven was opened and the Holy Spirit descended on him in bodily form like a dove. And a voice came from heaven: “You are my Son, whom I love; with you I am well pleased.” (Luke 3:21-22, NIV)

Luke seems to be saying that Jesus was baptized at the same time others were baptized. He didn’t hang back or wait for a private moment. It’s as if he wanted to express solidarity with the people who had accepted John’s message and decided to live God’s way.

Why did Jesus need to be baptized? It wasn’t a matter of repentance. In fact, Matthew tells us that when Jesus came to John to be baptized, John at first resisted, saying, “I need to be baptized by you, and do you come to me?” (Matt 3:14). John knew his own sin, and knew who Jesus was by contrast. But Jesus answered that this had to be done “to fulfill all righteousness” (vs. 15).

We sometimes use the phrase colloquially to mean that we need to meet all the proper and required expectations. Something similar might be said here. By submitting to baptism, Jesus isn’t repenting of his sin; he’s doing what God expects, publicly identifying with sinful humanity. In a sense, it’s the first act of his public ministry, an act that points forward to the way in which he will later take humanity’s sin upon himself in his crucifixion. It’s also an opportunity for Luke to show the Father, Son, and Holy Spirit working in unison: the Son obeys the Father; the Father declares his love; heaven opens, and the Son is empowered to do the Father’s will by the coming of the Holy Spirit.

Given what Luke says next, his emphasis seems to be on declaring Jesus to be the Son of God. Remember where we left Jesus at the end of chapter 2; the precocious twelve-year-old was puzzled that his distraught mother didn’t realize that he would be in the temple, in his Father’s house (Luke 2:49). And now at the end of chapter 3, Luke gives us a genealogy that concludes by calling Jesus “the son of Adam, the son of God” (3:38). Here’s how it begins:

Now Jesus himself was about thirty years old when he began his ministry. He was the son, so it was thought, of Joseph… (vs. 23)

People thought of Jesus merely as the son of Joseph the carpenter, but there was so much more to the story they didn’t know. I won’t give you the whole genealogy here (Luke 3:23-38), but I’d encourage you to read it on your own. More specifically, I’d recommend that you read it alongside the genealogy in Matthew 1. If you do, you’ll notice something that has puzzled interpreters for centuries: if the two genealogies are meant to trace Jesus’ ancestral lineage, why are they so different?

The simple differences are these. On the one hand, Matthew traces the lineage forward from Abraham, arranging it in a way that emphasizes Jesus’ descent from both Abraham and David. Luke, on the other hand, traces the lineage backward, past David, past Abraham, all the way to Adam and then to God.

The puzzle, however, is why all the names in the generations after David, all the way down to Joseph, are different. Whereas Matthew says that Jesus is descended from David through Solomon, for example, Luke says he’s descended from David through Nathan. At the other end, whereas Matthew lists Joseph’s father as Jacob, Luke names Joseph’s father as Heli.

As you might guess, different theories have been suggested, none of which can be proven. One is that Heli was not Joseph’s biological father, but Mary’s; Heli was Joseph’s father-in-law. Mary, in other words, was descended from David through Nathan, while Joseph was descended from David through Solomon. Either way, Jesus is of the line of David.

Still, why trace that line through Mary’s side of the family? Some read Matthew as emphasizing Jesus’ descent through a line of kings on Joseph’s side, in order to establish Jesus as the Messiah, the anointed king. That theme is clearly played out in the story of the magi and Herod the Great. Luke’s emphasis, by contrast, is to establish Jesus’ biological lineage. The explanation is plausible, but there’s no record of Mary’s lineage to corroborate it.

Another theory is that Heli and Jacob were half-brothers, having the same mother, but different fathers. One was Joseph’s biological father. The other became his legal father through Levirate marriage when his biological father died. This theory, too, solves the puzzle—but again, it can’t be proven.

What’s important here is that neither Luke nor Matthew is reporting mere facts obtained from the Hall of Records. Each traces the genealogy of Jesus in a specific way for theological reasons, not as a matter of ancestral curiosity. Jesus is descended from both Abraham and David. And for Luke, I think, the final phrase in his genealogy is telling: Jesus is “the son of Adam, the son of God.” Already in Luke’s gospel, Jesus was declared the Son of God by Gabriel (Luke 1:35); that sonship was illustrated by the exchange between Jesus and Mary in the temple (2:49), then declared again by the Father at Jesus’ baptism (3:22).

But as the church has declared through the centuries, Jesus is both fully divine and fully human: he is both the Son of God and the son of Adam. Just as Jesus acted in solidarity with sinful humanity in his baptism, so too would that solidarity save humanity on the cross. In Jesus, his Father is now our Father—and we too are God’s beloved.