Father Girardey explains that even a virtuous person needs to pray.
He writes: “However good and virtuous a man may be, he stands in constant need of divine grace to observe the commandments of God, to resist and overcome the temptations of the devil, the allurements of the world and the violence of his own passions, to perform the good works and duties of his state, and especially to persevere in the grace and friendship of God. But to be able to do all this, he must pray frequently and earnestly.”
“He who will not pray God for a necessary grace, does not really desire it; his lack of desire shows that he does not care for it, that he really does not want it. But, says St. Paul, ‘God is not mocked’ (Gal 6:7), and, therefore, He does not impart grace to him who does not want it or care for it. Hence the good, the just who neglect to pray for the graces they need, will lack the graces necessary for their perseverance, and will become spiritually weak and helpless, especially when assailed by strong temptations and by the violence of their passions, and the result will be that, sooner or later, they will fall into some grievous sin, lose the state of grace and God’s friendship and will run the risk of living and dying in sin, as has happened to so many, once virtuous and holy, for neglecting to pray in the time of temptation.”
“St. Alphonsus, Doctor of the Church, who has written so well and beautifully on prayer, maintains and proves that prayer is the ordinary sufficient grace which God gives to every man to enable him to save his soul, for if a man prays to God for the means of salvation, in all his spiritual wants, God will impart to him all that he needs to save his soul.”
“On the other hand, if the holiest person on earth were to neglect prayer, he would soon meet the same fate that befell St. Peter for not heeding the injunction of Jesus to watch and pray.”
Quotations from Ferreol Girardey, Prayer: Its Necessity, Its Power, Its Conditions (St. Louis: B. Herder, 1916).