One of Frank L. Sheed’s most popular books, and the one I think he considered his Meisterwerk, is Theology and Sanity. His thesis therein is, roughly, that right theology is the way to achieve right understanding of God, and, in turn, to have knowledge of God is the path to a sanitary destiny, i.e. to total sanity, i.e. to complete sanctity. There is a similar lexical link between wholeness and holiness, as well as between truth and loyalty. In the same vein, here’s a tiny riff of mine based on this comment at my self-introduction page:
It’s an interesting lexical issue, how “one,” “holy,” and “catholic” might all be rendered into the same concept, “whole” (or “full”). Hence: “I believe in the whole (or wholly) apostolic Church,” i.e. the Church that wholly captures and preserves the experience had by and the graces given to the Apostles by their intimate union with Jesus, the Incarnate Word. By being united with the “wholly Apostolic” Church, we can come as close to the same experience of our Lord, as far as I our eternal destiny is concerned, as they did.