This then helps to make sense of the structure of Peter’s argument in 1 Peter. Peter writes that the believers have been born again to love one another. He then quotes the passage from Isaiah to substantiate the point that they have been born of incorruptible seed – which is the Gospel. He then turns to specific aspects of their love (2:1), and how they are to live in this world.
The key here is the matter of doxa.
One aspect which is emphasized by the commentators relates to the interrelation of 1 Peter writing to “exiles” (1 Peter 1:1, 2:11) and Isaiah writing to exiles. The commentators, such as Achtemeier (142), Jobes (129-130) argue that contrasted doxa is the splendor and power of the world:
The author of 1 Peter and his readers face the mighty Roman Empire with all the glory of its culture and the might of its army. But for all their glory, the nations of the earth are nothing. (Jobes, 130).
That is completely true. The passage in Isaiah speaks largely as a comfort to the exiles – you will be returned. The passage in Isaiah, known as the “New Exodus” is here applied as comfort to the believers:
Verse 25 concludes with Peter’s commentary on the Old Testament citation. The word of the Lord in Isaiah, which represents the promise that God will restore his people from exile and fulfill his promises to Abraham (Gen 12:1–3), is ultimately fulfilled in the gospel proclaimed (euangelisthen) to the churches in Asia Minor. The new exodus, the return from exile, and the fulfillment of all God’s promises to Israel have become a reality through the gospel. Peter’s use of the word (euangelizō) almost certainly comes from Isaiah as well since in Isa 40:9 (the very next verse from the section Peter cited) “the good news” for Zion and Jerusalem is that God will come and fulfill his promises to Israel. As previously observed, Peter argued that the promises preached by the prophets were not intended for the prophets but for Christian believers. Similarly, he argued here that the promises in Isaiah are fulfilled in the proclamation of the gospel. Such are the privileges of Peter’s readers.
Thomas R. Schreiner, vol. 37, 1, 2 Peter, Jude, The New American Commentary (Nashville: Broadman & Holman Publishers, 2003), 97.
However, it is not clear the manner in which that statement ties to the need to love one-another. Ramsey sees the matter a bit more broadly:
Peter has no particular interest in the theme of poverty and riches, yet it is likely that his use of Isa 40:6–7 is analogous to that of James. His focus, however, is on Roman culture generally, whether in Rome or Asia Minor, rather than on the rich as a social class. The first part of the quotation can be understood as a comment on “the planting of perishable seed” to which he referred in v 23: “all humanity” (lit. “all flesh,” a common OT expression) is seen from the standpoint of its mortality, and human mortality is underscored by the metaphor of grass. Because the life cycle of plants is relatively short, and the perishability of plant life is more obvious and visible to humans than their own mortality, grass and flowers become appropriate metaphors (to Isaiah and Peter alike) for the human condition.
If πᾶσα σάρξ refers to humanity generally, πᾶσα δόξα αὐτῆς is probably intended to focus on the outward attraction or splendor of pagan society and of the “way of life that was your heritage,” a way of life that Peter has already characterized as “empty” (v 18; cf. Hort, 94). He does not deny the external beauty of pagan culture; it is as beautiful in its way as the wild flowers that God placed in the grassy fields, but it is also just as fragile and short lived. ἄνθος χόρτου is the LXX’s free translation of a Hebrew phrase meaning “flower of the field” (for a more literal rendering see Ps 102:15), and refers to actual flowers, not to the tiny blossoms of the grass.
Peter does not consciously choose the word δόξα (“glory”) to refer to this outward beauty; his use of Isa 40:6 makes it inevitable. Yet its occurrence in the Scripture quotation creates an appropriate contrast with the eschatological “glory” of Jesus Christ made possible by his resurrection (vv 11, 21) and waiting to be revealed to those who trust in him (v 7; 4:13; 5:1, 4).
J. Ramsey Michaels, vol. 49, 1 Peter, Word Biblical Commentary (Dallas: Word, Incorporated, 1998), 77-78. Belkin puts the matter more simply, “Human help is weak and perishable, but God’s promise of restoration can never fail” (41). Robert Leighton has a particularly beautiful digression on the temporary “glory” of man and the permanent “glory” of the Lord.
While these arguments all fit well within the overall context of the letter, it is not exactly certainly how this matter of perishing “glory” (doxa) relates to the matter of love.
Yet, if we consider doxa to be the loyalty the hesed of the world, we have a different understanding: Prior to being born again, hesed among the readers of the letter – the doxa of loyalty, reputation, honor – would have been nothing, an appearance which would fail before the Spirit of God (as it is in Isaiah).
However, the new birth of the believer is the restoration to what human beings are created to be:
The true glory of man, on the other hand, is the ideal condition in which God created man. This condition was lost in the fall and is recovered through Christ and exists as a real fact in the divine mind. The believer waits for this complete restoration.
Take now the ideas: hesed + what man was created to be = doxa.
An additional support for this connection can be found in Psalm 113:9 of the LXX—which is Psalm 115:1 of the English Bible:
Not to us, O LORD, not to us, but to your name give glory [doxa/kabod], for the sake of your steadfast love [Hesed] and your faithfulness! Psalm 115:1 (ESV)
In this Psalm, the “glory” (doxa, LXX) of God is God’s hesed. The ideas are also closely linked in Proverbs 21:21:
Whoever pursues righteousness and kindness [Hesed] will find life, righteousness, and honor [kabod/doxa]. Proverbs 21:21 (ESV)
To seek hesed is to obtain doxa.
Finally, in Exodus 33:18-19, the doxa is used to translate kabod (glory) in verse 18, and then tob (goodness) in verse 19. Moreover, the “doxa” (tob/goodness) of God in verse 19 is his mercy (hnh). This passage shows that the LXX’s translators understood doxa to carry a broader meaning than simply “glory/splendor”.
Let’s see if this fits Peter’s argument:
You have been set apart for God for love.
This is because you have been born again.
Your birth was not from the corruptible seed of this age, but with incorruptible seed, the living and abiding Word of God.
Let me show you from Scripture: Isaiah prophesized “comfort” to the people of God in exile who thought all was lost. He told them that all the hesed (covenant loyalty, mercy, loving kindness) of humans beings would perish – the word of men could not be trusted –, but God’s Word – His Hesed – would never fail. You have been born of that same word, you have as part of what you an imperishable hesed. That is the doxa of God. That word is exactly what was preached to you.
And what was preached to you? That God has kept his word and had rescued human beings through the death, burial and resurrection of Jesus Christ. What greater demonstration of hesed could there be? God loved us when we did not love him (Rom. 5:8). The love to which you were born flows directly into the love which you show:
7 Beloved, let us love one another, for love is from God, and whoever loves has been born of God and knows God. 8 Anyone who does not love does not know God, because God is love. 9 In this the love of God was made manifest among us, that God sent his only Son into the world, so that we might live through him. 10 In this is love, not that we have loved God but that he loved us and sent his Son to be the propitiation for our sins. 11 Beloved, if God so loved us, we also ought to love one another. 12 No one has ever seen God; if we love one another, God abides in us and his love is perfected in us. 1 John 4:7–12 (ESV)
In short: the Glory of God is God’s hesed. That imperishable glory produces true abiding love in human beings. This is unlike the “glory” of man which is really no glory – it is an appearance which can produce nothing lasting – certainly not love.