You need organizational Christianity—most fundamentally the local church, but also all the other kinds of institutions committed, as institutions, to advancing Christ. These are the only places where the special work of the Spirit in the hearts of believers can fully reach expression in shared life—where we can have koinonia that permeates the rhythms of the organizational culture and shapes our rules and policies. We need these places to ground us and to equip us, and also to carry out certain special functions the mission of Christ requires.
But that’s not where people live most of life. Most of life takes place in a culture we share with unbelievers, and if we’re not building people up to practice discipleship and spread the joy of God in those places, we’re mostly wasting our time. By definition, organizational Christianity can’t carry the joy of God into those structures of culture outside the church; we need a mode of Christian cooperation that’s more organic, something that subsists in our relationships and personal interactions rather than formal institutions.