St. Peter of Damaskos was an Eastern bishop of the eighth century. His writings appear in the Philokalia, an influential compendium of spiritual writings revered in the Orthodox church. In his work on the eight stages of contemplation he mentions yielding to the Holy Spirit when He "interrupts" your normal prayer routine:
When, however, God's grace kindles a sense of deep penitence in the heart, you should allow your intellect to be bathed in tears of compunction, even if this means that your mouth stops reciting psalms and your mind is made captive to what St. Isaac the Syrian calls 'blessed captivity'. For now is the time to harvest, not plant.
He also quotes St. Isaac's description of someone in a state of pure prayer:
Often it happens that a person so concentrates his intellect during prayer that, like Daniel the prophet, he falls unbidden to his knees, his hands outstretched and his eyes gazing at Christ's Cross; his thoughts are changed and his limbs are made weak because of the new thoughts that arise spontaneously in his intellect. (from the Mystic Treatises)
St. Peter adds that "the more habitual these thoughts become, the more the longing for God draws us on to understand and worship the Father ' in Spirit and in truth', as the Lord said. St. Paul also indicates this when he says: 'I would rather speak five words whose meaning I understand than ten thousand words in a strange tongue' (1 Cor. 14:19); and again: 'I wish that men would pray everywhere, lifting up holy hands without anger and quarrelling' (1 Tim 2:8)."
He concludes that singing hymns is a remedy for weakness, but "the experiences of rapture mark the perfection of the intellect."
Here is an example of the charismatic and liturgical working together in the spiritual life of the Eastern church. If you are sensitive to the action of the Holy Spirit, then don't be surprised if He interrupts your regularly scheduled prayer rule. Don't be afraid to fall on your knees, lift holy hands, and even pray in tongues. Here are two eastern saints, Peter of Damaskos and Isaac the Syrian, who testify to this reality.
*Quotations from "The Philokalia, Vol III". Palmer, Sherrard, & Ware, ed. trans. London: Faber & Faber, 1984