“The body, in fact, and it alone, is capable of making visible what is invisible: the spiritual and divine. It was created to transfer into the visible reality of the world, the mystery hidden since time immemorial in God, and thus to be a sign of it.”
– Pope John Paul II
The entire Theology of the Body catechesis hinges on this point.
A sign is something that points us to a reality beyond itself and, in some way, makes that transcendent reality present to us. Wind and breath are physical realities that point us to the Holy Spirit. For human beings, wind and breath make visible the invisible mystery of the Holy Spirit, in a concrete way.Similarly, the body, which is made in the image and likeness of God, is a physical, concrete sign that makes visible that which is invisible. The sign (the body) is indispensable in “making visible” the invisible divine mystery of God.