Teresa of Avila compares the human person and in particular the human soul with a castle in order to show that the relationship between the triune God and the human person presupposes interiority. The relationship doesn’t just happen between two persons (as for Buber), but implies reciprocal immanence. The article attempts to evaluate the use of spatial language in speaking of the soul and proposes to interpret spatiality as a way of expressing the person’s involvement in life and activity. Penetrating into the castle would thus signify being involved in one’s actions. In this perspective, making one’s way to the centre of the castle implies all dimensions and the entire life of the person, engaged in the relationship with God.