Ephesians 4:1-10 (NRSV)
I therefore, the prisoner in the Lord, beg you to lead a life worthy of the calling to which you have been called, 2 with all humility and gentleness, with patience, bearing with one another in love, 3 making every effort to maintain the unity of the Spirit in the bond of peace. 4 There is one body and one Spirit, just as you were called to the one hope of your calling, 5 one Lord, one faith, one baptism, 6 one God and Father of all, who is above all and through all and in all. 7 But each of us was given grace according to the measure of Christ's gift. 8 Therefore it is said, "When he ascended on high he made captivity itself a captive; he gave gifts to his people." 9 (When it says, "He ascended," what does it mean but that he had also descended into the lower parts of the earth? 10 He who descended is the same one who ascended far above all the heavens, so that he might fill all things.)
Imagine Jesus walking through Clemmons, N.C. What would He think as he passes Clemmons United Methodist, Clemmons Baptist, Clemmons Presbyterian, Clemmons Moravian? What would run through Jesus' mind as he passes the other churches in the community? In this mix of congregations there would be rich, poor, conservative, and progressive. There would be single persons, families, young, and old. Many churches would be welcoming, others not so much. How would Jesus feel as He thinks about all the opinions, closely held beliefs, and the things that divide and separate us into different sects, churches, and faith practices?
If you could ask a first century Christian, "are you going to church this Sunday?" they wouldn't know what you were talking about. The church was not a building. It was not a place that they went. It was a movement. It was people.
We forget that we do not "go to church." We are the church. The church is not a denomination or sect, or a group, it is people. One of the ways that we stay true to our calling as people of God is to remember that we are a holy place with a holy responsibility. When I think of Holy, I think of the character of the individual and also the character of the Body of Christ as a whole. The Apostle Paul reminded the people of Ephesus that they were "called to be Holy" through the process of personal and communal transformation.
To be Holy as a church means that we are individually and collectively led by the Spirit to be followers of Jesus Christ. We are called to be holy not only when we are together but when we leave this place of worship and discipleship to enter the world. Luke Timothy Johnson writes that
Becoming a saint has classically been understood as a deeper incorporation into the story of Jesus, so that believers might increasingly and ever more spontaneously share the faith of Jesus in God and express Jesus' self-sacrificial love toward others. Insofar as the church remains a community in which such transformation is possible, it retains something of its essential purpose. 
To be Holy, Johnson says, is even more than the growth of individual saints. It is also community, the Body of Christ in the world witnessing to the power and presence of the resurrected Christ. To be Holy is Jesus in the world every day. Think about it.
Luke Timothy Johnson, The Creed: What Christians Believe and Why it Matters (New York, NY: Doubleday Books, 2003), 267.