I like how Christopher Wright (Mission of God, 311-312) talks about the political nature of the early Christian church:
"But the early Christian community was not marked solely by its affirmation of a claim [Jesus is Lord] that subverted the political pretension of the empire. It was also a radically prophetic community, for they sought to live out within the present old order of the world the truths and values of the in-breaking new order of the kingdom of God. This new community, consciously shaped by the eschatological outpouring of God's Spirit, chose to express their spiritual unity through as much economic equality as they could achieve, so that none need be poor within their midst. They were taught by the apostles, who insisted that a primary duty of Christians was not just to witness and evangelize but do 'do good' (as Paul urges seven times in one tiny letter to Titus) and to be models of practical love in a world full of hatred. They were to be good citizens and pay their taxes, but also to recall that God's mandate to the state authorities (who are 'servants of God') was to do justice, punish wickedness and reward goodness (Rom 13:1-7). They accepted that political authorities were there by God's appointment, but they would not have forgotten the words of the prophets, who declared that governments that perverted justice stood under God's ultimate judgment (e.g., Jer 22:1-5). And they were reminded, in true prophetic style, by James not only that faith without practical action of love and justice is dead but also that it was till part of the apostolic duty of the church (as much as the prophetic duty of old) to denounce in no uncertain terms the oppressive practices of unscrupulous employers who feed their obscene luxury on the tears of those they exploit (James 2:14-17; 5:1-6). No, the early Christians, with all their unbounded evangelistic energy, were not lacking in awareness of the radical implications of their faith for the political, social, and economic world around them."