As I have been reading through D.A. Carson’s new book Christ and Culture Revisited I came across a very helpful definition of “culture” that seems to provide a key to understanding the relevance of the Gospel in man’s environment. Richard Neibuhr offers this definition of “culture,” as we typically understand the word “culture:”
Culture is the “artificial, secondary environment” which man superimposes on the natural. It comprises language, habits, ideas, beliefs, customs, social organization, inherited artifacts, technical processes, and values. 1
The key to understanding the relevance of the Gospel in the midst of various cultures is the fact that cultures themselves are “secondary, artificial environments.” So what is the primary, natural environment of men? It seems that this is where the Bible’s self-witness to man as the imago Dei, but now fallen, dead in sins, without God, and needing nothing less than resurrection from the dead, is the environment in which all men find themselves. The “culture” of man–if I may use the term as applied to the natural environment of man–is the culture of living in God’s world, suppressing the truth in unrighteousness, and needing redemption. If this is how we understand what under girds every “culture” (to use the word in its secondary, sociological sense) then the Gospel is always relevant regardless of what we think we need to do with it in order to make it relevant. All of this is not to say that we do not need to be sensitive to the “cultural” differences that exist among our neighbors. We do not want to unnecessarily offend our neighbor in our attempt to bring the Gospel to them. But the reality is that the Gospel, as the Gospel, will offend until God chooses to make it the message of life to life unto those who will be saved.
 D.A. Carson Christ and Culture Revisited (Grand Rapids: Wm. B. Eerdmans, 2008) p. 11