The word ‘prayer’ . . . refers to a period of standing or a particular act of worship; for while engaged in his reading, an ascetic is never for one moment devoid of the upsurges of prayer. For no reading of Scripture which has engaged in this spiritual concern will be empty of the fountain of prayer, seeing that for the most part this person will be inebriated by the mysteries he encounters. Profound prayers will appear unawares in him in a wondrous way, without his having prepared or willed them. And why do I call ‘prayer’ his frequently being inebriated by some insight, seeing that no place is to be found there any longer for the stirring or recollection of prayer? This is something much more excellent—insofar as this can be said—even than the level of prayer. Prayer, however, is lower in rank than being stirred in spirit: on this there is no dispute, for prayer is inferior to this mystery. Frequently, when the intellect is stirred by some insight produced by events either in the natural world or in the Scriptures as it perceives their spritual intention and then peers, with the help of the grace which accompanies it, into the Holy of Holies of their mysteries, then there is not even the strength to pray. . . . When the intellect is given permission and accorded the strength to enter therein, no strength or movement or activity is left remaining in the senses during these periods. There is someone from among those who are gathered here who has always experienced these things: I know that his heart immediately leaps up when he encounters this kind of reading which comes from the experience and from indications of the things just mentioned.
St Isaac the Syrian, II/30,8-11, quoted by Bishop Hilarion Alfaev, The Spritual World of Isaac the Syrian (Cistercian Publications, 2000), pp 234-235.