The place of breathing techniques (i)
In the treatise of Simeon the New Theologian about the three forms of prayer, in the works of Nikephoros the Monk, and in the Century of Kallistos and Ignatios Xanthopoulos—all contained in the Philokalia—the reader will find instructions about the technique whereby the mind can be introduced into the heart with the aid of physical breathing—in other words, a mechanical method designed to help us achieve inner prayer. This teaching of the Fathers has created and continues to create many perplexities for its readers, although in fact there is really nothing difficult about it. We advise our beloved brethren not to try to practice this mechanical technique unless it establishes itself in them of its own accord. Many who have attempted to learn it by practical experienced have damaged their lungs and achieved nothing. The essential thing is for the mind to unite with the heart at prayer, and this is accomplished by divine grace, in its own time, determined by God. The mechanical method described in these writings is fully replaced by an unhurried repetition of the prayer, a brief pause after each prayer, quiet and steady breathing, and enclosing the mind in the words of the prayer. With the aid of such means we can easily achieve a certain degree of attention. Before long the heart begins to be in sympathy with the attention of the mind as it prayers. Little by little the sympathy of the heart with the mind begins to change into a union of mind and heart; and then the mechanical technique suggested by the Fathers will appear by itself. All the mechanical methods of a material character are suggested by the Fathers solely as aids for a quicker and easier attainment of attention during prayer, and not as something essential. The essential, indispensable element in prayer is attention. Without attention there is no prayer. True attention, given by grace, comes when we make our heart dead to the world. Aids always remain no more than aids. The union of the mind with the heart is a union of the spiritual thoughts of the mind with the spiritual feelings of the heart.
--Bishop Ignatii
[Igumen Chariton of Valamo, The Art of Prayer (Faber and Faber, 1966), 104-105]