St. Catherine of Siena (03) Self-knowledge: From the Opening Passage in the Dialogue

The soul, who is lifted by a very great and yearning desire for the honor of God and the salvation of souls, begins by exercising herself, for a certain space of time, in the ordinary virtues, remaining in the cell of self-knowledge, in order to know better the goodness of God towards her. This she does because knowledge must precede love, and only when she has attained love, can she strive to follow and to clothe herself with the truth. But, in no way, does the creature receive such a taste of the truth, or so brilliant a light therefrom, as by means of humble and continuous prayer, founded on knowledge of herself and of God; because prayer, exercising her in the above way, unites with God the soul that follows the footprints of Christ Crucified, and thus, by desire and affection, and union of love, makes her another Himself. Christ would seem to have meant this, when He said: To him who will love Me and will observe My commandment, will I manifest Myself; and he shall be one thing with Me and I with him. In several places we find similar words, by which we can see that it is, indeed, through the effect of love, that the soul becomes another Himself.