79 It must also be borne in mind that there is question here of a hidden mystery, which during this earthly exile can only be dimly seen through a veil, and which no human words can express. The Divine Persons are said to indwell inasmuch as they are present to beings endowed with intelligence in a way that lies beyond human comprehension, and in a unique and very intimate manner which transcends all created nature, these creatures enter into relationship with Them through knowledge and love. If we would attain, in some measure, to a clearer perception of this truth, let us not neglect the method strongly recommended by the Vatican Council in similar cases, by which these mysteries are compared one with another and with the end to which they are directed, so that in the light which this comparison throws upon them we are able to discern, at least partially, the hidden things of God.
Source: Mystici Corporis Christi (Vatican.va)