4 as it is written in the book of the words of the prophet Isaiah: “A voice of one crying out in the desert: ‘Prepare the way of the Lord, make straight his paths. 5 Every valley shall be filled and every mountain and hill shall be made low. The winding roads shall be made straight, and the rough ways made smooth, 6 and all flesh shall see the salvation of God.’”
Luke casts the call of John the Baptist in the form of an Old Testament prophetic call (Luke 3:2) and extends the quotation from Isaiah found in Mark 1:3 (Isaiah 40:3) by the addition of Isaiah 40:4-5 in Luke 3:5-6. In doing so, Luke presents the theme of the universality of salvation, which he has announced earlier in the words of Simeon (2:30-32). Moreover, in describing the expectation of the people (3:15), Luke is characterizing the time of John’s preaching in the same way as he had earlier described the situation of other devout Israelites in the infancy narrative (2:25-26, 37-38). Later, in 3:7-18 Luke presents the preaching of John the Baptist who urges the crowds to reform in view of the coming wrath (Luke 3:7, 9: eschatological preaching), and who offers the crowds certain standards for reforming social conduct (Luke 3:10-14: ethical preaching), and who announces to the crowds the coming of one mightier than he (Luke 3:15-18: messianic preaching).
Luke is keenly interested in the impact his gospel story will have not simply on the world as kosmos – the world, that is, conceived most generally – but also on the world as oikoumene – the world as it is constituted by the political, economic, and religious powers. John’s preaching of repentance, because it will literally turn people away from the powers that be to the Lord, threatens those invested in the present order.
Perhaps this is why Luke extends the quotation from Isaiah also employed by Mark and Matthew. The advent of the one John anticipates will not only straighten paths, but also fill valleys, bring down mountains, straighten what is crooked, and smooth that which is rough (3:5). In this light, it is perhaps not surprising that further on in the story, John’s preaching will ultimately lead to his beheading by one of those named in Luke 3:1, while Jesus will still later be crucified by another. Those who are threatened by repentance and forgiveness, after all, will not go without a fight.
Luke adds the other verses – those about the transformation of the ups and downs, and sideways-ness of life into straight and smooth and level paths. While this image can lead to the idea of reversal. That is, the rich become poor and the poor become rich. It seems more likely that Luke intends a meaning of equality. That is, the rich and poor meet in the middle. I think that part of this equality is Luke emphasis that in the God’s kingdom (and church) human differences don’t matter. There will be rich and poor. There will be slaves and free. There will be males and females. There will be young and old. There will be Jews and Gentiles. All are invited. We might say, there is a level playing field for all people.
This thought is emphasized in the last line of the quote: “All flesh shall see the salvation of God.” Luke stresses the universal aspect of God’s salvation. The only other time this particular word for “salvation” is used (soterion) in all of the gospels, is when Simeon sings: “..my eyes have seen your salvation, which you prepared in the sight of all peoples, a light for revelation to the Gentiles and glory for your people Israel” (2:30-32). What did Simeon see when he declares he has seen God’s salvation? He had seen the infant Jesus and there was a change in Simeon’s thinking about death.
Later in the gospel a closely related word is used (soteria) when Jesus tells Zacchaeus, “Today salvation has come to this house” (19:9). What had come to his house? Jesus had invited himself over and there was change in Zacchaeus’ thinking about wealth.
It is the power of the encounter with Jesus – the condition for the possibility of seeing salvation.