St. Francis of Sales, as we read in his life, efficaciously experienced the power of this prayer. At seventeen years of age, he was living in Paris, engaged in study, and at the same time wholly devoted to pious exercises and holy love of God, which gave him a perpetual foretaste of heavenly joy.
At this time the Lord, to try his faith, and attach him more strongly to his love, permitted the devil to represent to him that his efforts were in vain because he was already condemned by the divine decree. The darkness and dryness in which it pleased God to leave him at the time for he was insensible to all consoling thoughts of the divine goodness, caused this temptation to have more power over the heart of the holy youth; so that through great fear and desolation he lost his appetite, sleep, colour, and cheerfulness, and excited the compassion of all those who looked upon him. Whilst this horrible conflict lasted, the saint could conceive no other thoughts and utter no other words but those of sorrow and distrust.
“Shall I, then” he said, as it is related in his life, “be deprived of the favour of my God, who hitherto has shown himself so gracious and so kind to me? Oh, love! oh beauty ! to which I have consecrated all my affections, shall I never more enjoy your consolations? Oh Virgin mother of God, the most beautiful of all the daughters of Jerusalem, am I then never to see thee in paradise? Ah, my Lady! if I am never to see thy lovely face, do not permit me to be forced to blaspheme and curse thee in hell.”
These were the tender sentiments of that afHictted heart, still so enamoured of God and the Virgin. This temptation lasted for a month, but at length, the Lord was pleased to deliver him from it by means of the consoler of the world, most holy Mary, to whom the saint had before made a vow of chastity, and upon whom he used to say he had placed all his hopes. One evening, on returning home, he entered a church, where he saw a small tablet suspended from the wall; he found written on it the prayer of St. Augustine:
“Remember, oh most merciful Mary! that no one, in any age, was ever known to have fled to thee for help and found himself abandoned.”
He prostrated himself before the altar of the divine mother, and recited with deep feeling this prayer; he renewed his vow of chastity, promised to recite daily the rosary, and then added: “Oh my queen, be my advocate with thy Son, whom I dare not approach. My mother, if in the other world I should be so unhappy as not to be able to love my Lord, whom I know is so worthy to be loved, at least obtain for me that I may love him as much as I can in this world. This is the grace that I ask of thee, and from thee, I hope for it.”
Thus he supplicated the Virgin, and then abandoned himself to the divine mercy, resigning himself entirely to the will of God. But hardly had he finished his prayer, when by his most sweet mother he was suddenly freed from temptation ; he immediately recovered his interior peace, and with it health of body, and from that time continued to live a most devout servant of Mary, whose praises and mercies he never ceased to proclaim in his preaching and his writings to the end of his life.
Source: Glories of Mary by St Alphonsus Liguori