"Since, as everyone realizes, holiness of life is the fruit of the exercise of the will inasmuch as it is strengthened by the aid of divine grace, God has made abundant provision lest we should at any time lack the gift of grace, if we desire it. We can obtain it, in the first place, by constant prayer.
There is, in fact, such a necessary link between holiness and prayer that the one cannot exist without the other.
The words of Chrysostom on this matter are an exact expression of the truth: “I consider that it is obvious to everyone that it is impossible to live virtuously without the aid of prayer;”[39] and Augustine sums up shrewdly: “He truly knows how to live rightly, who rightly knows how to pray.”[40]"
https://www.papalencyclicals.net/pius10/p10haer.htm
