The paper presents the story of a contemporary Thomistic debate that deals with a crucial theological question, i.e. whether or not our knowledge of God is related to his nature/essence, and its legacy to theology of our time. Throughout the last 60 years there has been an intense debate among Thomist scholars belonging to different generations: R. Garrigou Lagrange, E. Gilson, H. McCabe, F. Kerr, J. Wippel, M. Pérez de Laborda, D. Turner and I. McFarland. The legacy from this debate is that both in contemporary philosophical and revealed theology a cautious distinction is needed: while it is legitimate and profitable to apply contemporary anti-essentialist criticism to natural and social sciences and, also, to cosmology and philosophical anthropology, this should not be done in regards of God. In fact, in God, because of his non-changeability and simplicity, everything is of his essence, and this essence is unknowable.