Ex quo intellectus noster divinam substantiam non adaequat, hoc ipsum quod est Dei substantia remanet, nostrum intellectum excedens, et ita a nobis ignoratur: et propter hoc illud est ultimum cognitionis humanae de Deo quod sciat se Deum nescire, in quantum cognoscit, illud quod Deus est, omne ipsum quod de eo intelligimus, excedere.
(Thomas Aquinas, Quaestiones disputatae de potentia Dei, q. 7, art. 5, ad 14)
It is because human intelligence is not equal to the divine essence that this same divine essence surpasses our intelligence and is unknown to us: wherefore man reaches the highest point of his knowledge about God when he knows that he knows him not, inasmuch as he knows that that which is God transcends whatsoever he conceives of him. (tr. the English Dominican Fathers)