"The blessed soul of Christ himself does not have this comprehensive understanding; only the unique Son of God who is in the womb of the Father enjoys it. . . . No one . . . [will ever] comprehend [(comprend)] the divine essence except God alone, Father, Son, and Holy Spirit [(Anima autem Christi Deum cognoscendo non comprehendit, quia hoc non dicitur, nisi de unigenito, qui est in sinu patris. . . . Nullus enim divinam comprehendit essentiam, nisi solus Deus pater, et filius, et spiritus sanctus)]."
St. Thomas Aquinas, Super evangelium S. Ioannis lectura, cap. 1, l. 11, as quoted by J.-P. Torrell, in his "Saint Thomas d'Aquin, maître de vie spirituelle," Revue des sciences religieuses 71, no. 4 (1997): 456 (442-457), italics mine. The Latin is taken from the Turin (i.e. Marietti) edition of 1952 ed. Raffaele Cai, as reproduced by Corpus Thomisticum here: http://www.corpusthomisticum.org/cih01.html#87429 (where there is much more, including the distinction between seeing the divine essence tota and totaliter).