St. Theodoros The Great Ascetic - 56 - 58

56. You must avoid continually wasting time outside your cell, if you have indeed chosen to practice stillness. For it is most harmful, depriving you of grace, darkening your mind and sapping your aspiration. This is why it is said: 'Restlessness of desire perverts the guileless intellect' (Wisd. 4:12). So restrict your relationships with other people, lest your intellect should become distracted and your life of stillness disrupted.

57. When sitting in your cell, do not act in a mindless and lazy manner. 'To journey without direction', it is said, 'is wasted effort.' Instead, work purposefully, concentrate your intellect and always keep before your eyes the last hour before your death. Recall the vanity of the world, how deceptive it is, how sickly and worthless; reflect on the dreadful reckoning that is to come, how the harsh keepers of the toll homes will bring before as one by one the actions, words and thoughts which they suggested but which we accepted and made our own. Recall the chastisements in hell, and the state of the souls imprisoned there. Recall, too, that great and fearful day, the day of the general resurrection, when we are brought before God, and the final sentence of the infallible Judge. Bring to mind the punishment that befalls sinners, the reproach, the reprobation of the conscience, how they will be rejected by God and cast into the age-long fire, to the worm that does not die, to the impenetrable darkness where there is weeping and gnashing of teeth (cf Mark 9:44, Matt. 8:12). Meditate on all the other chastisements, and let your tears continually drench your cheeks, your clothes, the place where you are sitting. I have known many men in whom such thoughts have produced an abundance of tears, and who in this way have wonderfully cleansed all the powers of their soul.

58. But think also of the blessings which await the righteous: how they will stand at Christ's right hand, the gracious voice of the Master, the inheritance of the heavenly kingdom, the gift which is beyond the intellect's grasp, that sweet light, the endless joy, never interrupted by grief, those heavenly mansions, life with the angels, and all the other promises made to those who fear the Lord.