I read Isaiah 43:16-28 as a messianic promise; there, Israel is actually described as covenant-breakers. I do not find anything there to stipulate a definition of "declaring God’s praise," and certainly not to define this "purpose" in terms of the incorporation of the nations into Israel in the way that the church is tasked to incorporate them. Isaiah 61 I likewise see as a messianic promise.

Chris, I must be missing something here. Isaiah speaks of Jacob, Israel, the chosen people, being redeemed from exile ‘that they might declare my praise’; more than that, the Spirit and blessing of God will be poured out ‘upon your descendants’ (Is.44:3). Peter uses exactly the same language to describe the ‘exiles of the dispersion… chosen and destined by God the Father’ (1 Pet.1:1-2): they are a priestly people, chosen ‘that you may declare the wonderful deeds of him who called you…’. How is this not a continuity of purpose? Of course, the old covenant had broken down: Israel’s prophets had forseen both that and the renewal of the covenant relationship through the Spirit. Perhaps it would be more helpful to speak of an analogy of purpose, but the effect is the same. Peter surely wants these new Christian communities to see themselves as being in functional continuity with Israel of the old covenant. The Old Testament does not envisage the incorporation of the nations into Israel: the people are blessed through the multiplication of descendants. Paul’s good news is that the Gentiles may now participate in this blessing because the conditions of membership have changed, but this need not affect the basic purpose of being a people of blessing amidst the nations, a priestly people charged with the worship and representation of the living God. We still have a covenant with the descendants of Abraham. This is must mean something.

If this is the case, the chief measure of the effectiveness of this people is not necessarily numerical increase; I would argue that what matters most is the quality of this representation of the reality of God. This is especially important in our post-Christendom world. I think that the hope of national revival, of a reversion to being a ‘Christian’ nation, is delusory. I want people to ‘come to Christ’, but I want them to know that in doing so they are becoming part of a holy people, a priestly nation, a temple for the Spirit of God in the world, chosen to play the same role in the world that was originally given to the physical descendants of Abraham.

Jesus came to a time and place where the people knew who God was, were aware of his actions in history, and were expecting his messiah. With Jesus, God moved on to a phase in which humanity in general is to be invited into fellowship with him.

This seems far too progressivist, far too idealistic to me. I think it seriously misunderstands the nature of the crisis that Israel faced in the 1st century and how that crisis shaped the emergence of the messianic movement. We are closer to biblical thinking, I would suggest, if we keep in view not some sort of strategic ‘plan’ in the mind of God but the history of a people. But this is altogether another story. For now, many thanks for your contribution to the discussion. I’m sorry if I come across as too argumentative.