The presented contribution demonstrates the role and process of mystical knowing in the spiritual experience and theology of John of the Cross. The Carmelite mystic of the 16 century uses the concept of mysticism as the profound experience of the mystery of Revelation of God in Christ: the term "mystic" is a synonym of the spiritual experience of unity.
The study reflects the role of "loving attentiveness" in the new grade of the cognition characterized by a combination of knowledge, love and trust.