True its not a building made of wood and stone. But its also not just isolated believers and their bibles scattered throughout the land. The Church = "the assembly" = the gathering together. Which presupposes elders, deacons, preachers of the Word, all in service to the corporate life of the body, organized worship service conducted in peace and unity, and accountability in Christian discipleship both as individuals and in a corporate setting. Lone ranger Christianity (much of American evangelicals) doesn't really exist in the New Testament anywhere.