Especially important is pure prayer–prayer which is unceasing and uninterrupted. Such prayer is a safe fortress, a sheltered harbor, a protector of virtues, a destroyer of passions. It brings vigor to the soul, purifies the intellect, gives rest to those who suffer, consoles those who mourn. Prayer is converse with God, contemplation of the invisible, the angelic mode of life, a stimulus towards the divine, the assurance of things longed for, ‘making real the things for which we hope’ (Hebrews 11:1)…Pray day and night. Pray at times of dejection and at times of exhilaration. Pray with fear and trembling, with a watchful and vigilant mind, so that your prayer may be accepted by the Lord. For, as the psalmist says: ‘The eyes of the Lord are on the righteous, and His ears are open to their prayer’ (Psalm 34:15).
…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…recall 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…But think also of the blessings which await the righteous…the inheritance of the heavenly kingdom, the gift which is beyond the intellect’s grasp, that sweet light, the endless joy….let these thoughts dwell within you, sleep with you, arise with you. See that you never forget them but, wherever you are, keep them in mind, so that evil thoughts may depart and you may be filled with divine solace.
~St Theodoros the Great Ascetic