OUR Lord said to the virgin Catherine [St. Catherine of Siena]: “The holy desire of the soul, that is to say, good-will, is a continual prayer, because it has the power of prayer. And, whatsoever man does for the love of God and of his neighbour, may be called prayer, since love is accounted as prayer.
Good-will and pious affections should, however, at certain seasons and hours, be raised to Me by actual devotion. Know, daughter, that the soul that perseveres in humble and faithful prayer, attains to all virtue.”
Source: https://archive.org/details/workslouisofbloi00bloiuoft (‘Spiritual Works of Louis of Blois)