One of the major and glorious choral sections in Handel's 'Messiah' has the choir singing over and over about 'the glory of the Lord, which all flesh will see together'. This is, of course, a repetition of Isaiah 40.5.
Luke, at Lk. 3.6, as is his want, is drawing on the LXX rather than the MT version of Isaiah 40.5, as there is a salient difference between the two versions. Lk. 3.6 reads "and the whole human race will see God's salvation'-- the other directed rescue work of God. The term 'glory' in the Hebrew has been rendered as 'salvation' in the Greek translation of Isaiah 40. 5. Apparently the translator of the LXX was convinced that glory=salvation here. Now this is very interesting indeed, and there are several minor points to unpack.
The first of these is the oft noted universalism of Luke, by which I mean that Luke stresses not that all human will eventually be saved, but that it is God's purpose and intent that all will be saved. Thus here the emphasis is on 'all flesh will see God's salvation'. This is simply the Lukan way of saying what we find in John 3.16-- God so loves the world and sent his only Begotten to save the world, not condemn it.
In Lk. 3.6 we have an echo of the speech of Simeon in Lk. 2.30-32-- "For my eyes have seen your salvation which you have prepared in the sight of all people, a light of revelation to the Gentiles, and for glory to your people Israel." Both Gentiles and Jews, both the previously non-elect, and the elect will be included in this revelation and salvation. Notice as well how the term glory parallels the term revelation in Lk. 2. 31-32.-- in fact the Greek literally reads 'a light for/unto revelation of the Gentiles and [for/unto] glory of your people Israel'. The revelation is for the Gentiles just as the glory is for Israel.
The second thing to stress about the quotation of Is. 40.5 in Lk. 3.6 is that since Luke follows the LXX here rather than the MT we must assume he agrees with the LXX rendering of the text, and is comfortable with the equation 'glory=salvation' here. What then does it mean to say God's salvation, which the whole race will see, is equivalent to God's glory? In the context of the Lukan discussion, he has already prepared us for the answer to the question in Simeon's speech in Lk. 2.32. Light of revelation to the Gentiles and light of glory to Jews is just two parallel ways of discussing the very same subject, which is salvation.
God's glory is manifest not only in revealing himself to both Gentiles and Jews. It is not just a matter of the demonstration of the divine presence or character to the world. No, Luke presses further for listen to what Simeon says before Lk. 2.32--- "For my eyes have seen your salvation, which you have prepared according to the face of all the people" (a literal rendering). In Lk. 2.30-32 then we hear in close succession about salvation, revelation and glory, all closely associated. The term salvation of course makes clear the end or aim of the revelation, and also the glory. The aim is the rescuing, saving, redemption of both Gentiles and Jews.
Here I think, in our wonderful Christmas story is as clear a revelation of the other-directed character of God, which involves God revealing, saving, and bringing glory to his people.
Luke was not the first to associate Isaiah 40.5 with eschatological salvation. We find this idea at Qumran as well at 1QS 8.14-15; 9.19-20, but also in Bar. 5.7 and Testament of Moses 10.3-4. It appears there were many thinking along these lines about Isaiah 40.5, associating glory with God's redemptive work. And here is the punch line. The glory of God is most revealed when God indiscriminantly saves people, whether they are part of his chosen people or not. The salvation 'which all flesh will see' reveals the real heart and character of God-- which is other directed, and self-sacrificial, even to the point of giving up his only Begotten Son. In other words, God doesn't just exhibit a covenant love to those whom he has always and already promised redemption, help healing-- his Jewish people. God comes and saves those he has made no promises to, and has had no covenant relationship with at all! Paul explains further the nature of this radical indiscriminant love in Romans 5--"You see at the right time , when we were still powerless, Christ died for the ungodly... while we were still sinners, Christ died for us...when we were God's enemies, we were reconciled to God through the death of his Son...'
Throughout the Psalms, and in various places in the OT, we hear about God vindicating the righteous, the upright, the holy. What is different about the Gospel, whether in Luke or in Paul, is the theme of the saving/justifying/setting right of the unrighteous, the sinners, the enemies of God, which has as its presupposition 'all have sinned and fallen short of the glory of God'. This was a scandalous message then, and it still is now. How dare God do that?
The baby lying in the manger reminds us, not of the inherently righteous character of those God came to favor. It reminds us not of the inherently good character of all humanity. It reminds us that in spite of everything we have become, God still loves us, and has provided a means by which we may be saved, if we will but respond to the Good News, if we will but welcome this one child into our homes and lives.
Handel was right when he finished writing Messiah and said 'I did think I saw heaven open, and the glory of God revealed'. Indeed, what redounds to God's glory more than anything else is his salvation plan of other-directed love that includes the least, last, and lost, as well as the first, most, and found. The Hound of Heaven has come down, and is on the loose in the world, in the form of an unassuming, beguiling child. Christmas is for everyone, everywhere--- but will you merely 'keep Christmas', or will you give it away?
This is a Christmas message worth celebrating forever.