Martin Bucer's De Regno Christi (On the Kingdom of Christ) is an utterly fascinating book, revealing better than any text I know the tensions and contradictions that dogged the Reformers' attempts to simultaneously retain a strong ecclesiology and strong view of the civil authorities' role in promoting the kingdom.
The chief question I brought to this text was: Is the Church in itself the kingdom of Christ, or is the kingdom the joint work of Church and State under Christ's lordship? Bucer begins by unequivocally stating the former, and articulating what seems to be a robustly political idea of the Church--it is itself a kingdom, analogous to, but set over against, "the kingdoms of this world," which refers to all political powers, Christian or secular. The Church too is a kingdom that seeks to unite its citizens in a community peace, in the pursuit of a common good that affects every area of life, and which seeks to order the lives of each to assist the whole, but it does so through the word, not the sword. With the Church as such a seemingly autonomous political entity, standing over against even Christian civil governments, one wonders how Bucer is going to take this treatise in the Erastian direction that we all know he is going to.
But then he begins citing Scripture passages that describe the kingdom, and what seemed so solid, physical, corporate, and political begins to vanish into mist.
The Church/Kingdom is depoliticized by becoming increasingly spiritual, inner, and individual in Bucer's description, even as he comments on Biblical prophecies where it is robustly tangible and this-worldly. As he came to each verse, I waited with bated breath, hoping he wouldn't vaporize it; when he started exegeting Is. 61:1-6, I even scribbled in the margin, "No, don't do it, Martin!" But he did.
Here's the passage from Isaiah:
"The Spirit of the Lord God is upon me, for the Lord to anoint me; to evangelize the meek he has sent me, and to heal the brokenhearted, to announce liberty to captives and the opening of prison to those who are bound. To announce the year of the good pleasure of the Lord, and the day of the vengeance of our God, to console those who mourn. To propose consolation to the mourners of Zion, to give them a glory instead of ashes, an oil of gladness instead of mourning, to mantle them with praise instead of a grieving spirit, to call them trees of righteousness, the planting of the Lord for glory. They shall build up the places which have been waste for ages, and they shall raise up buildings which have been from their beginning desolate, and they shall restore cities which have been waste and desolate for many generations. And foreigners shall stand and feed your flocks, and aliens shall be your farmers and vinedressers. But you will be called the priests of the Lord; they shall say that you are the ministers of our God; you shall enjoy the wealth of nations, and in their esteem you shall be lifted up."
Here's some excerpts from Bucer's remarks on it:
"Second: it is the sum and substance of the gospel to proclaim the forgiveness of sins through Christ to the penitent, for those who do not yet have this in faith are captives of Satan, detained in the prison of eternal perdition. Third: only those who have a contrite heart, i.e., regret their sins with true repentance, receive the gospel of salvation....Fifth: whoever are true citizens of the Kingdom of Christ should plainly manifest that they are trees of righteousness and plantings of the Lord, planted to show forth his glory, so that all may see this clearly and proclaim accordingly....And so the light of faith should shine forth in every church of Christ from every Christian, so that all, 'seeing their good works, may glorify the Father, who is in heaven.' ... Sixth: it is the duty of the citizens of the Kingdom of Christ that they restore all the old ruins that have lain waste for many ages, i.e., that they lead many peoples who for generations have been deprived of any knowledge and love of God to faith in Christ and the development of righteousness."
Of course, all these things are true about repentance of sin, faith, and individual righteousness, but if this is all you can see even in a passage as robust as this one, then yours is a poor and ethereal gospel indeed.