"God is Spirit, and those who worship him must worship in Spirit and truth."
From the Dominicans:
"'God is spirit, and those who worship him should worship in spirit and in truth' (John 4:24). So prayer is not damaged by the kind of attentiveness which makes us pray in spirit."
- St. Thomas Aquinas, Commentary on the Sentences, Book 4, Distinction 15, Question 4, from Albert & Thomas: Selected Writings, The Classics of Western Spirituality, Paulist Press. 1988, pg. 379.
From the footnote to that quote from St. Thomas, by Simon Tugwell, O.P.:
"The move in Latin from adorare (worship) to orare (prayer) is easy; exactly the same use of this text is found in Peraldus (cf. Tugwell, Early Dominicans p. 167). The Marginal Gloss on John 4:24 identifies "spirit" as "the innermost temple of the heart," and says that it is in this temple that "prayer is to be made to God."
It is interesting to remember that St. Teresa of Avila would have heard Dominican preachers in the Cathedral of Avila while she was growing up. Whether she specifically heard them preaching on this passage, quoting Peraldus or Thomas, or whether she derived her idea of an interior castle from another one of the several Dominicans who influenced her thinking, she does not mention anywhere as far as I know. However, the "attentiveness which makes us pray in spirit", as St. Thomas said, sounds somewhat like the recollection of prayer in which St. Teresa of Avila would advise people to collect their faculties and enter into themselves, into the Interior Castle of their souls in prayer.
From the Carmelites:
This is how she explains her "Interior Castle":
"Now let us return to our beautiful and charming castle and discover how to enter it. This appears incongruous: if this castle is the soul, clearly no one can have to enter it, for it is the person himself: one might as well tell some one to go into a room he is already in! There are, however, very different ways of being in this castle; many souls live in the courtyard of the building where the sentinels stand, neither caring to enter farther, nor to know who dwells in that most delightful place, what is in it and what rooms it contains.
Certain books on prayer that you have read advise the soul to enter into itself, and this is what I mean. I was recently told by a great theologian that souls without prayer are like bodies, palsied and lame, having hands and feet they cannot use. Just so, there are souls so infirm and accustomed to think of nothing but earthly matters, that there seems no cure for them. It appears impossible for them to retire into their own hearts; accustomed as they are to be with the reptiles and other creatures which live outside the castle, they have come at last to imitate their habits. Though these souls are by their nature so richly endowed, capable of communion even with God Himself, yet their case seems hopeless. Unless they endeavour to understand and remedy their most miserable plight, their minds will become, as it were, bereft of movement, just as Lot’s wife became a pillar of salt for looking backwards in disobedience to God’s command.
As far as I can understand, the gate by which to enter this castle is prayer and meditation. I do not allude more to mental than to vocal prayer, for if it is prayer at all, the mind must take part in it. If a person neither considers to Whom he is addressing himself, what he asks, nor what he is who ventures to speak to God, although his lips may utter many words, I do not call it prayer".
- St. Teresa of Avila, The Interior Castle, the First Mansions, translated by the Benedictines of Stanbrook, Christian Classics Ethereal Library.
One more quote, along the same lines, from St. Paul of the Cross, describing St. Catherine of Siena:
"She fashioned a beautiful oratory within her soul, where she was always at prayer in the midst of her household work. You should do that, and you well know how often I have recommended that. Often arouse your soul to love of God and embrace him with holy affections within."
- St. Paul of the Cross, - St. Paul of the Cross, letter to Teresa Palozzi (11), September 8, 1759, from The Letters of St. Paul of the Cross, Vol. III (1759-1775), translated by Roger Mercurio, C.P., and Frederick Sucher, C.P., edited by Laurence Finn, C.P., and Donald Webber, C.P., c. 2000, New City Press, Hyde Park, N.Y., p. 32.
St. Paul of the Cross was certainly influenced by St. Teresa of Avila's Interior Castle. Teresa, in turn, was clearly influenced by the early Dominicans, and perhaps by St. Thomas Aquinas as introduced to her by a sixteenth century Dominican.
There were several Dominicans who influenced St. Teresa. In The Life, Teresa mentioned her father's Dominican confessor, Father Vicente Barron, as "a man of great learning" (Chapter 5). She also was acquainted with the Dominican Father Garcia de Toledo, a famous Dominican from a noble family, who was her confessor at one time. Her younger brother Antonio became a Dominican.
Moreover, when she finished writing Interior Castle, it was a Dominican theologian, Father Diego de Yanguas, who reviewed it in her presence together with Father Jeronimo Gracian, who had asked her to write the book. Father Yanguas was Teresa's confessor at one time, who had ordered her to burn the manuscript of her Meditations on the Song of Songs, which she did (although a clandestine manuscript survived). Father Gracian was the son of a secretary in the court of Charles V, who would have understood the concept of Christ as a king in the interior of a castle. ,In the section quoted above from Interior Castle, Teresa mentions a "great theologian" who told her a story about prayer, but she does not attribute to him her idea of an interior castle, and does not name him -- knowing that a Dominican theologian, Father Yanguas, would read the book when she finished it.
While she may have initially derived the basic concept from the Dominicans, her elaboration of it is one of comfort, diversity, and love with implications different from those of the original Dominican concept. The difference between an inner temple and an inner castle seems to be largely the sense of being in a home with many rooms, and the sense that Christ is the King, His Majesty in the center of the castle. Her Interior Castle, thus, differs from the Dominican Innermost Temple in ways that can be derived from Teresa's reflections on moving from room to room within the Castle as we move, for example, from simple prayer to meditation to the prayer of quiet and back again -- something one does not do in a Temple. A castle, in her day, would also be an elaborate and comfortable home, protected from the reptiles and vermin that would be found outdoors and perhaps just inside the entrance of the ground floor level. It has a sense of being at home, or in the King's home, in prayer, which distinguishes the Interior Castle's implications from the implications of the Dominican concept of an inner temple.
Thus, despite distinctions between the two concepts, the connection between her interior castle and the early Dominicans' innermost temple is so close that we could easily include John 4:24, and its understanding by the early Dominicans, among the foundational Scriptures for Teresian spirituality, directly or indirectly.