The Gospels are full of it. Consider Jn. 14, 24: “He who has my commandments and keeps them, he it is who loves me. But he who loves me will be loved by my Father, and I will love him and manifest myself to him.” Or Jn. 2, 3: “And by this we can be sure that we know him, if we keep his commandments. He who says that he knows him, and does not keep his commandments, is a liar and the truth is not in him.”
So, the only way to know God is to be like God, and God has revealed Himself to be Three Persons that are so in relation that they are One God. Not that they are “one being,” but that they are irreducibly Three Persons – which means that you cannot one without the other. And this because there is an ontological connection that is who their very Selves is. That is, the Father is not the Son since the Son says: “The Father is greater than I” (Jn. 14, 28). But at the same time, “I and the Father are one” (Jn. 10, 30).
The only way to understand this is to change epistemological wavelengths, viz. the “Being” of the Father is the act of engendering the Son, such that no Father, no Son; and vice versa: no Son, no Father.
Consider Benedict XVI’s recent remark summarizing the scriptural presentation of the Person of Christ:
“Recent theology has rightly underlined the use of the word ‘for’ in all four accounts, a word that may be considered the key not only to the Last Supper accounts, but to the figure of Jesus overall. His entire being is expressed by the word ‘pro-existence’ - he is there, not for himself, but for others. This is not merely a dimension of his existence, but its innermost essence and its entirety. His very being is a ‘being-for.’ If we are able to grasp this, then we have truly come close to the mystery of Jesus, and we have understood what discipleship is.”
Once you can handle that - i.e. to be is not simply to be “there” as a static “Dasein” but to be relation “for” (which is other than the way we see things) – then it becomes “clear” that the only way to “know” a divine Person is to experience oneself to be relating, such as love as going out of self.
You would also have to understand that there is another kind of knowing than through the senses. We all know this kind of knowing since it is what we understand by consciousness but we cannot explain it by going to what we normally understand and explain by “knowing” in terms of ideas/concepts. Wojtyla explains that consciousness is that background “knowing” that is the experience of the self that is somehow in motion, such as sensing, acting, receiving. This is the knowing of such internal experiences such as good, bad, responsible, guilt, peace, joy, etc.
The first reading of the Office of Readings today (Memorial Day, 5/30/2011 says: “The way we can be sure of our knowledge of him is to keep his commandments. The man who claims, ‘I have known him,’ without keeping his commandments, is a liar; in such a one there is no truth. But whoever keeps his word, truly has the love of God been made perfect in him. The way we can be sure we are in union with him is for the man who claims to abide in him to conduct himself just as he did….The man who claims to be in light, hating his brother all the while, is in darkness even now. The man who continues in the light is the one who loves his brother” (Jn. 1-11).
What could this knowledge of Christ be except the experience of the obedience to the commandments, the first of which is to love? The CCC #2558 quotes St. Therese of Lisieux: “For me, prayer is a surge of the heart; it is a simple look turned toward heaven, it is a cry of recognition and of love, embracing both trial and joy.” And why is this exodus of the self a source of knowledge except that it is an experience of the being that is the self?
Wojtyla burrows deep to find the source of this knowledge. He finds it in experience and asserts apodictically: “Experience is always the first and most basic structure of the cognizing subject, and this experience, in keeping with the dual structure of the cognizing subject, contains not only a sensory but also an intellectual element. For this reason, one could say that human experience is already always a kind of understanding. It is thus also the origin of the whole process of understanding, which develops in ways proper to itself, but always in relation to this first stage, namely, experience. Otherwise I see no possibility of a consistent realism in philosophy and science. The image of the world that we produce in them could then be basically at odds with reality.
“This also applies to the human being as the object of philosophical anthropology. The basis for understanding the human being must be sought in experience – in experience that is complete and comprehensive and free of all systemic a priories. The point of departure for an experience of human action that includes the lived experience of moral good and evil as an essential and especially important element; this experience can be separately defined as the experience of morality. These two experiences – the experience of the human being and the experience of morality – can really never be completely separated, although we can, in the context of the overall process of reflection, focus more on one or the other. In the case of the former, philosophical reflection will lead us in the direction of anthropology; in the case of the latter, in the direction of ethics.”
Wojtyla continues with the process of self-determination. The power of self-determination appears to be the will, but by the “will” he understands “the whole person.” “When I say that the will is the power of self-determination, I do not have in mind the will all alone, in some sort of methodical isolation intended to disclose the will’s own dynamism. Rather, I necessarily have in mind here the whole person. Self-determination takes place through acts of will, through this central power of the human soul. And yet self-determination is not identical with these acts in any of their forms, since it is a property of the person as such. Although my whole discussion here takes place on the phenomenological plane of experience, still, in the light of the discussion, St. Thomas’ distinction between substance and accident and between the soul and its powers (in this case, the will), becomes especially apparent. My analysis, however brief, shows that self-determination is a property of the person, who, as the familiar definition says, is a naturae rationalis individua substantia. This property is realized through the will, which is tan accident. Self-determination – or, in other words freedom – is not limited to the accidental dimension, but belongs to the substantial dimension of the person: it is the person’s freedom, and not just the will’s freedom, although it is undeniably the persons’ freedom through the will.”
Wojtyla’s point is to suggest that “Self determination reveals that what takes place in an act of will is not just an active directing of the subject toward a value. Something more takes place as well: when I am directed by an act of will toward a particular value, I myself not only determine this directing but through it I simultaneously determine myself as well. The concept of self-determination involves more than just the concept of efficacy: I am not only the efficient cause of my acts, but through them I am also in some sense the ‘creator of myself.’ This is huge. We have here a major point. When I determine myself and own myself, and I make the gift of self, I literally become who I am. Being the image of God, if I make the gift relationally, I become “good” as God is “Good.” I experience and know myself as “good” and therefore love myself . We have here also the theology of work whereby the working person by self mastery and self-gift becomes “another Christ.” By the experience of self-mastery I know myself and I know God being the image of God.
Let me add then-Josef Ratzinger's remarks [L'Osservatore Romano n. 22, 3 June 1998 p. 16] on Christian faith as experience:"My observations refer to the question of experience and faith, and to the problem of instituion and life. Various Fathers have correctly stated that for the proclamation of Christ's Gospel one's own spiritual experience is a fundamental condition. Only those who know God through a personal encounter can make God known to others: only those who live in a deep relationship with Christ can guide others to communion with the Lord. However, it is important to distinguish between faith and experience. Faith is a gift from God, almost an anticipation given to the us by diivne love, which precedes our action. IN faith, God opens his heart to us and communictes himself; experience is thus the appropriation and personalization of faith. Therefore, faith is common and universal; the experience of it is in itself personal and individual. Only faith unites and synthesizes our always fragmentary experiences; faith is the criterion and measure of experience, the guide that gives its light on the path of our experience.
In addition, true faith and humility go together. Faith is not a merit of mine; it is not the fruit of the depth of my interior journey, but an anticipation given by God to our poverty. To believe is to submit to divine sovereignity, an insertion into the common measure of the Wor od God. An arrogant faith would be a contradiction, would seem an absolutizing of one's own doctrine, whereas faith is actually a strippoing of oneself and communion with Jesus Christ, the Son of God and our servant.
This is very different from, say, Maritain’s “preconscious life of the intellect.” He writes: “we possess in ourselves the Illuminating Intellect, a spiritual sun ceaselessly radiating, which activates everything in intelligence, and whose light causes all our ideas to arise in us, and whose energy permeates every operation of our mind. And this primal source of light cannot be seen by us; it remains concealed in the unconscious of the spirit.
“Furthermore, it illuminates with its spiritual light the images from which our concepts are drawn. And this very process of illumination is unknown to us, it takes place in the unconscious; and often these very images, without which there is no thought, remain also unconscious or scarcely perceived in the process, at least for the most part.
“Thus it is that we know (not always, to be sure!) what we are thinking, but we don’t know how we are thinking; and that before being formed and expressed in concepts and judgments, intellectual knowledge is at first a beginning of insight, still unformulated, a kind of many-eyed cloud which is born from the impact of the light of the Illuminating Intellect on the world of images, and which is but a humble and trembling inchoation, yet invaluable, tending toward an intelligible content to be grasped.”
“I have insisted upon these considerations because they deal with the intellect, with reason itself, taken in the full scope of its ife within us. They enable us to see how the notion of a spiritual unconscious or preconscious is philosophically grounded. I have suggested calling it, also, musical unconscious, for, being one with the root activity of reason, it contains from the start a germ of melody. In these remarks, on the other hand, we have considered the spiritual unconscious from the general point of view of the structure of the intellect, and with regard to the abstractive function of intelligence and to the birth of ideas. It was not a question of poetry. It was even a question of the origin and formation of the instruments of that conceptual, logical, discursive knowledge with which poetry is on bad terms. Well, if there is in the spiritual unconscious a nonconceptual or preconceptual activity of the intellect even with regard to the birth of concepts, we can with greater reason assume that such a nonconceptual activity of the intellect, such a nonrational activity of reason, in the spiritual unconscious, plays an essential part in the genesis of poetry and poetic inspiration. Thus a place is prepared in the highest parts of the soul, in the primeval translucid night where intelligence stirs the images under the light of the Illuminating Intellect, for the separate Muse of Plato to descend into man, and dwell within him, and become a part of our spiritual organism.”
 BXVI, “Jesus of Nazareth” II, Ignatius (2011) 134.
 K. Wojtyla, “The Personal Structure of Self-Determination,” Person and Community, Lang (1993)190.
 J. Maritain, “Creative Intuition in Art and Poetry,” Meridian Books – Noonday Press (1955) 73-74.