God commissioned me to preach among you His Word in its fullness, that mystery hidden from ages and generations past but now revealed to his holy ones. God has willed to make known to them the glory beyond price which this mystery brings to the Gentiles– the Mystery of Christ in you, your hope of glory. (Col 1: 25-26
The Church as a mystery balances the human and the spiritual aspects of the Church. Since part of the nature of the Church is spiritual, it is through the eyes of faith that we can see the hand of God accomplishing things in the Church, that which could not be done by humans alone.
The Mystery of the Church as Witnessed in History
The history of the Church show how the Church has survived different forms of sufferings and persecutions; how she stood the test of time in spite of her limitations and weaknesses; and how she sustained and empowered the people to remain steadfast to their faith.