A great effort and much toil are needed in prayer before we can reach a state in which our mind is no longer troubled, and so attain the inward heaven of the heart where Christ dwells. As St. Paul says, 'Do you not realize that Christ dwells within you, unless you are worthless?' (cf. 2 Cor. 13:5).
When said with pain, the prayer gives birth to mourning. Mourning brings tears. Tears in turn give birth to purer prayer. For tears like a fragrant myrrh wash away the filth, and thus the inbreathing of God is cleansed, which like a dove is confined within four walls, as if made of the four elements.... And then, as soon as the walls break down and collapse, the dove immediately flies to the Father whence it came.
Prayer is a branch (of a tree) of meekness, and freedom from anger. Prayer is an expression of joy and thankfulness. Prayer is a remedy against sorrow and depression.
Pray firstly to be purified of passions, secondly to be freed from ignorance and forgetfulness, and thirdly to be delivered from all temptation and forsaking.
When you are praying, don’t rack your brains to find words. On many occasions the simple, monotonous stammering of children has satisfied their Father who is in heaven. Don’t bother to be loquacious lest the mind is bewildered in the search for words. The tax-collector gained the Lord’s forgiveness with a single sentence, and a single word charged with faith was the salvation of the robber. Loquacity in prayer often fills the head with foolish fancies and provokes distractions. Brevity on the other hand - sometimes only one word is enough - in general favors recollection.
The one who prays ought never to halt his movement of sublime ascent toward God. For just as we should understand the ascent 'from strength to strength' as the progress in the practice of the virtues, 'from glory to glory' (2 Cor. 3:18) as the advance in the spiritual knowledge of contemplation, and the transfer from the letter of sacred writing to its spirit, so in the same way the one who is settled in the place of prayer should lift his mind from human matters and the attention of the soul to more divine realities.
When you are praying alone, and your spirit is dejected, and you are wearied and oppressed by your loneliness, remember then, as always, that God the Trinity looks upon you with eyes brighter than the sun; also all the angels, your own Guardian Angel, and all the Saints of God. Truly they do; for they are all one in God, and where God is, there are they also. Where the sun is, thither also are directed all its rays. Try to understand what this means.
Until we have acquired true prayer, we are like those who introduce children to walking. Make the effort to raise up, or rather, to enclose your mind within the words of your prayer; and if, like a child, it gets tired and falters, raise it up again. The mind, after all, is naturally unstable, but the God Who can do everything can also give it firm endurance. Persevere in this, therefore, and do not grow weary...
Prayer requires the inseparable presence and cooperation of the attention. With attention, prayer becomes the inalienable property of the person praying; in the absence of attention, it is extraneous to the person praying. With attention, it bears abundant fruit; without attention, it produces thorns and thistles. The fruit of prayer consists in illumination of mind and compunction of heart; in the quickening of the soul with the life of the Spirit. Thorns and thistles are a sign of deadness of soul and pharisaical self-esteem which springs from the hardening of a heart which is contented and elated by the quantity of the prayers and the time spent in reciting those prayers.