This, my son, is how you should begin your life according to God. You should continually and unceasingly call to mind all the blessings which God in His love has bestowed upon you in the past, and still bestows for the salvation of your soul. You must not let forgetfulness of evil or laziness make you grow unmindful of these many and great blessings, and so pass the rest of your life uselessly and ungratefully. For this kind of continual recollection, pricking the heart like a spur, moves it constantly to confession and humility, to thanksgiving with a contrite soul, and to all forms of sincere effort, repaying God through its virtue and holiness. In this way the heart meditates constantly and conscientiously on the words from the Psalms: “What shall I give to the Lord in return for all His benefits towards me?”
Thus the soul recalls the blessings of God’s love which it has received from the moment it came into existence: how it has often been delivered from dangers; how in spite of having often fallen by its own free choice into great evils and sins, it was not justly given up to destruction and death at the hands of the spirits of deception; and how God with long-suffering overlooked its offences and protected it, awaiting its return. It also recalls that although through the passions it had become the willing servant of hostile and malicious spirits, He sustained it, guarding it and in all ways providing for it; and finally that He guided it with a clear sign to the path of salvation, and inspired it with the love of the ascetic life. So He gave it the strength gladly to abandon the world and all the deceitfulness of worldly pleasure, adorning it with the angelic habit of the monastic order, and providing for it to be received by holy men in an organized brotherhood.
Can any man consciously call these things to mind and not be moved always to contrition of heart? Having so many pledges from past blessings, will he not always have firm hope, in spite of the fact that he himself has so far done nothing good? He will say to himself: “Though I have done nothing good and have committed many sins before Him, living in uncleanness of the flesh and indulging in many other vices, yet He did not deal with me according to my sins, or reward me according to my iniquities, but gave me all these gifts of grace for my salvation. If, then, from now onwards I give myself completely to His service, living in all purity and acquiring the virtues, how many holy and spiritual gifts will He not grant me, strengthening me in every good work, guiding and leading me aright.” If a man always thinks in this way and does not forget God’s blessings, he encourages and urges himself on to the practice of every virtue and of every righteous work, always ready, always eager to do the will of God.
St Mark the Ascetic. From the Letter to Nicolas the Solitary. Philokalia 1.148-149