Given Díaz’s training in trinitarian theology, it is clear why St. John of the Cross’s writings would draw his attention. As Bernard McGinn puts it in The Essential Writings of Christian Mysticism, ...

St. Teresa has left a classical dscription of the sort of life led by these first Discalced Carmelites, in chaps.xiii and xiv of her "Book of Foundations". John of the Cross, as he now called ...