9 He also told this parable to some who trusted in themselves that they were righteous and regarded others with contempt:
10 "Two men went up to the temple to pray, one a Pharisee and the other a tax collector.
11 The Pharisee, standing by himself, was praying thus: 'God, I thank you that I am not like other people: theives, rogues, adulterers, or even like this tax collector.
12 I fast twice a week; I give a tenth of all my income.'
13 But the tax collector, standing far off, would not even look up to heaven, but was beating his breast and saying, 'God, be merciful to me, a sinner!'
14 I tell you, this man went down to his home justified rather than the other; for all who exalt themselves will be humbled, but all who humble themselves will be exalted."
from: Chris' Lent One sermon:
In essence, Abbot Isaac's advice to his young questioners is this — find a word or short phrase as a prayer, and learn to say it continually until it goes into your heart. This, along with some variations, forms the central practice which the church has historically called contemplative prayer. It is a kind of pure prayer practice that does not rely on thinking about what you want to say to God and then sending off your well designed missive. Rather, it takes Jesus at his word that when praying "your Father knows what you need before you ask him". It is also the Orthodox Church's authorised way of learning how to fulfil the injunction of St Paul to "pray without ceasing" which Orthodox people do by saying the so-called "Jesus prayer" which is "Lord Jesus Christ, Son of God, have mercy on me a sinner". We have this in our liturgy as the kyrie, but the Eastern Churches make it a central and continuous form of contemplative prayer.