Both are gifts of God, but one serves the other. The institutional church serves to uphold the mystical church, to ensure its propagation and to invite and welcome people to encounter its mystery. But it is the nest where the real eggs are hatched.
Many of the frustrations and hurts of Christians are rooted in getting tied up in the institutional church, which is all about programs, property, and personalities. The institutional church is not bad, not at all. It's just imperfect to be human, and the church is not immune to being human. In fact, we should be the first to stand up and say we are all broken, for our entire purpose is to point to the One who brings healing and wholeness and transforms our hurts with grace. When the institutional church sins, it sins boldly and trusts God to redeem us, rather than pretending that what we are doing is perfectly in the will of God.
A healthy and vibrant institutional church knows deep in its bones that there is a deeper movement underneath the surface. It's not a matter of recovering the mystical church, it's already there. It's a matter of uncovering, not recovering. The Spirit is at work and we are the body of Christ, bound together with a love that is beyond our human ability to love.
The mystical church is the fine wheat in the midst of tare. But where would we be if both churches did not co-exist, graced by God to grow?
The institutional church seeks converts, members, and volunteers. The mystical church seeks Jesus. The first serves to make the second possible, adn we give God the glory.