For God is silence, and in silence is he sung by means of that psalmody which is worthy of Him. I am not speaking of the silence of the tongue, for if someone merely keeps his tongue silent, without knowing how to sing in mind and spirit, then he is simply unoccupied and becomes filled with evil thoughts: ... There is a silence of the tongue, there is a silence of the whole body, there is a silence of the soul, there is the silence of the mind, and there is the silence of the spirit.
(John the Solitary, 'On Prayer'; Philokalia)
'The Philokalia: The Complete Text (Vol. 1); Compiled by St. Nikodimos of the Holy Mountain and St. Markarios of Corinth'
By G. E.H. Palmer (Translator), Philip Sherrard (Translator), Kallistos Ware (Translator)
The Philokalia is a collection of texts written between the fourth and fifteenth centuries by spiritual masters of the Orthodox Christian tradition. First published in Greek in 1782, translated into Slavonic and later into Russian, The Philokalia has exercised an influence far greater than that of any book other than the Bible in the recent history of the Orthodox Church.