Richard Lovelace writes that the church must "fully appropriate the life and redemptive benefits of Jesus Christ" (Dynamics, p. 191), because if it doesn't it will fall into one of two damaging forms of enculturation. By the way, enculturation can be defined as the process of adopting the characteristics and norms of another culture. On the one hand, if the church isn't experiencing a renewed understanding of the life and redemptive benefits of Christ, it will absorb elements of its host culture that it should judge as unholy (destructive enculturation). On the other hand, if the church isn't being renewed in the Gospel of Christ, another dangerous alternative sometimes comes about: the church works so hard to separate itself from the broader culture that it "re-creates" the rigidity of the Old Testament's emphasis on the geographical and ethnic separation of God's people from the rest of the world (protective enculturation).
A few thoughts on the protective enculturation of the OT: the separateness of Israel from the rest of the world served an important purpose in the history of redemption: 1) to teach us that God's people were to be set apart and distinct from the surrounding peoples and nations but also 2) to show us that God's people needed a work of conversion and renewal that would run deep into the interior of God's people, for hearts to be set apart for God ultimately (consider Peter's words to those "scattered" throughout Asia Minor- 1Pet. 2:9- the issue isn't one of locale, but one of hearts being "called out" of darkness and into light). In a word, we learn in the OT that while the people could be taken out of the world, the worldliness could not be taken out of the people; a greater work of renewal and redemption was needed. So in Matt. 1:21, the child to be named Jesus is described as One who will "save his people from their sins," a salvation actually reaching to the defective layers of the heart (Jer. 17:9) to renew it and make one fit to ascend the Lord's holy hill (Psa. 24:3).
Lovelace reviews the ways sixteenth century Protestants were simply being enculturated in a destructive manner by the unholy aspects of fallen culture and losing their distinctiveness altogether. As a result, reform movements of the sixteenth century "such as Puritanism and Pietism, sought to develop a Protestant style of piety by tinkering with monastic spirituality and adapting it to a Reformational theological base. This inevitably sent them back to the ascetic ideals of the early church fathers, which they did not entirely rethink. And so the Puritans, shuddering a little at Luther's 'freedom of the Christian man' which they feared would lead to licentiousness and dead orthodoxy, reintroduced the training-code morality which forbade the theater, the dance, cosmetics and novel clothing style, and added to the older list of taboos on the use of playing cards, religious graphic art, the employment of musical instruments in worship, the celebration of Christmas and other indifferent things. Abandoning the Reformers' use of Sunday as a day of rest, recreation and reflection on the works of God, they turned the Sabbath into a day of strenuous holy work with recreation tabooed. They rigorously abandoned holy days like Christmas and Easter but introduced in their place fifty-two new fast days per year" (Dynamics, p. 193).