St. Mark the Ascetic
Even though knowledge is true, it is still not firmly established if unaccompanied by works. For everything is established by being put into practice. Often our knowledge becomes darkened because we fail to put things into practice. For when we have totally neglected the practice of something, our memory of it will gradually disappear. For this reason Scripture urges us to acquire the knowledge of God, so that through our works we may serve him rightly. When we fulfill the commandments in outward actions, we receive from the lord what is appropriate; that any real benefit we gain depends on our inward intention. If we want to do something but cannot then before God, Who knows our hearts, it is as if we have done it, this is true whether the intended action is good or bad.
The intellect does many good and bad things without the body, whereas the body can do neither good nor evil without the intellect. This is because the law of freedom applies to what happens before we act.
Similarly, those who pray are protected from despair... Do you see how every virtue that is performed to the point of death is nothing other than refraining from sin? Now to refrain from sin is from within our own natural powers, but not something that buys us the kingdom.
While men can scarcely keep what belongs to him by nature, Christ gives the gift of sonship through the cross.
There is no perfect prayer unless our mind evokes the Lord.
Prayer is the mother of all virtues.
Excerpted from The Philokalia, Vol. 1 pages 126, 7