“Let the man of study then be perpetually listening for truth. When he bends over his work, the Spirit breathes in him, reveals Himself perhaps from outside, sends His prophets — men, things, books, happenings; the attentive soul must neglect nothing of it all; for this spirit of truth, like grace, often passes by and does not come back. Is it not indeed itself a grace?”
Sertillanges, Antonin G., O.P. The Intellectual Life: its Spirit, Conditions, Methods. (Washington, DC: The Catholic University of America Press, 1987), page 124.