The church is indispensable in God’s kingdom. The church alone is his local, gathered community washed in the blood of his Son under the oversight of earthly shepherds. (There is no such thing as the “invisible” church in the Bible.) The church alone preserves structured theological belief (orthodoxy). The church alone is the pillar and buttress of truth (1 Tim. 3:15). The church alone administers the sacraments, or ordinances. The church is God’s chief institution for maturing his people (Eph. 4:1–16).
But the church isn’t God’s central work in the earth, and it certainly isn’t his only work. His chief work is his kingdom (Mt. 6:33), his rule and reign, to which institutions like family, church, and state contribute. The church is a single divinely established institution among several, and to elevate it to a more domineering place leads to the blight of ecclesiastical colonization. 
Because the church is obviously vital, many Christians get the idea that where God is at work in the world, he is working everything within the church. This ecclesiastical colonization has historically come in one of two forms: (1) the role of the church is expanded to dominate all of life: family, education, politics, and culture. All culture must be church-ruled culture. The Middle Ages sometimes perpetuated this error, which we can designate as ecclesiocracy — the rule of the church. This isn’t a problem anywhere in the Western world today.
But there’s also (2): The role of Christianity is contracted to conform to the church. It’s this second problem that’s pervasive today. The only important Christian things are happening in the church; everything outside the church is secondary or irrelevant as far as the Faith is concerned. The idea that culture itself should be Christian is a huge mistake. Because economics, politics, science, technology, entertainment and sports aren’t a part of the church, they need and should not be Christian. This error is apparent in the so-called “Two-Kingdom” Theology: the kingdom of the church is governed by the Bible, but the kingdom outside the church is regulated by “natural” theology, on what both Christians and non-Christians can agree are common-sense, non-Christian principles: Jesus is an absentee landlord. This dualism always leads to a radically secularized culture and a radically pietized church. The culture abandons God, and the church abandons any field it can’t control. From Satan’s standpoint, it’s an ideal arrangement.
Privileging Theology, De-privileging Worldview
Ecclesiastical colonization starts early. In seminaries and Bible colleges, future church leaders are taught the nearly exclusive importance of theology, meaning biblical or systematic theology and including exegesis, hermeneutics, Christology, soteriology, eschatology, and ecclesiology. These topics are necessary, and there can be no robust Faith without them, but the Bible includes much more. The Bible is no less concerned with a Christian view of economics, sex, music, science, and education than with traditionally theological categories. The Bible tells us how we are to live in the world, not just in the church. In fact, the faith disposition of our heart generates a worldview, and this worldview and the philosophy we derive from it shape how we interpret reality — including how we read the Bible.
The culture abandons God, and the church abandons any field it can’t control. From Satan’s standpoint, it’s an ideal arrangement.
Our hearts and minds must be turned toward the Triune God before we can encounter the Bible reverently, and this is why the basic elements of a Christian worldview and philosophy come before even God-honoring Bible reading. Theology, the kind of knowledge central in the church, is not the only knowledge, or even the first knowledge, that needs to be Christian. Our view of reality precedes our view of everything else. It must begin with God and move outward to the world and family and culture and church and all else.
To better grasp Ecclesiastical colonization, think of the double-decker tour buses in London. Ecclesiastical colonizers move all Christianity into the upper deck of the church and theology. On the lower deck they leave the rest of life as permissibly non-Christian. Christians assume the Bible has nothing relevant to teach about tax rates or foreign policy or education standards or architecture or popular music or movies or cloning or surrogate motherhood or medical care: these are issues that shouldn’t pose big arguments and “everybody should work them out for himself.” The only important matters are evangelism and prayer (mostly in the church) and AWANA programs and Beth Moore Bible studies and church leadership conferences. The upper deck alone is Christian.
Meanwhile, the lower deck gains its independence from Christianity. Why? The bus driver is always on the lower deck. The lower deck, already unattached from the Bible and church and Christianity, jettisons the upper deck, and soon starts driving the entire culture, above which the detached upper deck angelically floats, enjoying its helium holiness, while the lower deck drives the vast majority of cultural riders straight to hell. For this reason Joseph Boot writes: “To limit the kingdom of God to the church is to surrender culture to the enemies of God.”
The temptation to surrender to ecclesiastical colonization is fierce. Living in a radically secular and neo-pagan culture, we feel safe retreating into our churches and ignoring the outside world. But Satan will never respect the sanctity of our churches. His objective in de-sacralizing culture is eventually to de-sacralize the church and family. Our counter-objective must be to re-sacralize all of life. The intention of the kingdom of God is to colonize all of life for Jesus Christ.
 P. Andrew Sandlin, Un-Inventing the Church (La Grange, California: Center for Cultural Leadership, 2007).
 S. U. Zuidema, Communication and Confrontation (Toronto: Wedge Publishing, 1972), 47.
 Christopher Dawson, Medieval Essays (Freeport, New York: Books for Libraries Press, 1954, 1968), 75–94.
 David VanDrunen, “Calvin, Kuyper, and ‘Christian Culture,” in Always Reformed, R. Scott Clark and Joel E. Kim, eds. (Escondido, California: Westminster Seminary California, 2010), 135–153.
 Brian G. Mattson, Cultural Amnesia (Billings, Montana: Swinging Bridge Press, 2018).
 Andree Troost, What Is Reformational Philosophy? (no loc.: Paideia Press, 2012), 1–21.
 No author listed [Joseph Boot], For Mission (Grimsby, Ontario: EICC Publications, 2018) 20.