Missional leaders and congregation view the world through the lens of a Christian world-view.
Being culturally relevant can squeeze church people into a mold they would rather resist. The old adage, "it take ones to know one" tempts us to put on cool shades when we determine how to engage the culture, meaning that if we're not careful, we will view our mission through a lens colored by the times rather than through the eternal Word of God and person of Christ. The pressure to identify is so great that many congregations abandon the distinctives of faith in order to gain a foothold in the world out there. What a miscalculation. You see, the mission is lost if the point of reference shifts. Shoot, looking through the wrong lens makes them the mission field, and not the missionaries. Strategic mistake!
Like the term missional, world-view is another buzzword. Basically, world-view is the lens by which each of us views and assesses life. More specifically, it is the framework of ideas and beliefs by which people interpret the world and what is happening. Of course, there are many conflicting world-views, about as varied as there are diverse populations, world religions, cultures, languages, and many other political, economic, and social values. Today, the prevailing world-views as related to American culture are the Biblical world-view and the secular humanist world view. To learn more about world views you can check here or here, and many other useful sites.
The point is very simple. Many individuals and institutions, seeking to be missional and make the connection that engages the world around them do so at the cost of trading their Biblical world-view for something more palatable. This is often both theological and methodological, the core of the belief system that moves them, and the way the mission is attempted as a result of those beliefs. So, today many congregation advocate behaviors and practices that don't sync with Scripture, morphed by the pressure of public opinion and pop trends. So, the ailments of the culture become the diseases of the church. Who's influencing who is the question?
At the top of this slippery slope is a low view of Scripture. You see, if the Bible is not totally reliable, if it is always under question, and is not the authority in all areas of life, everything else is just fluid, go with the flow, drift with the currents, submerge under the waves. This is the starting point of the secular humanist world-view, the relativism of life, the Dalmatian theory of Scripture, only authoritative in spots. Congregations and leaders without a Biblical world-view cannot be genuinely missional. They're just do-gooders. And, we don't need another civic club.
Missionalists see the world through the lens provided by the God who created it.