We can illustrate this with a couple of examples. Philosophy can only be acquired if we philosophize, if we carry through the process of philosophical thought; mathematics can only be appropriated if we think mathematically; medicine can only be learned in the practice of healing, never merely by means of books and reflection. Similarly, religion can only be understood through religion -- an undisputed axiom in more recent philosophy of religion. The fundamental act of religion is prayer, in which the Christian religion acquires a very specific character: it is the act of self-surrender by which we enter the Body of Christ. Thus it is an act of love. As love, and with the Body of Christ, it is always both love of God and love of neighbor, knowing and fulfilling itself as love for the members of this Body.
[Prayer is] the central act of the person of Jesus and, indeed, that this person is constituted by the act of prayer, of unbroken communication with the one he calls "Father." If this is the case, it is only possible really to understand this person by entering into this act of prayer, by participating in it. This is suggested by Jesus' saying that no one can come to him unless the Father draws him (John 6:44). Where there is no Father, there is no Son. Where there is no relationship with God, there can be no understanding of him who, in his innermost self, is nothing but relationship with God, the Father -- although one can doubtless establish plenty of details about him. Therefore a participation in the mind of Jesus, i.e., in his prayer, which is an act of love, of self-giving, and self-expropriation to men, is not some kind of pius supplement to reading the Gospels, adding nothing to knowing of him or even being an obstacle to the rigorous purity of critical knowing. On the contrary, it is the basic precondition if real understanding, in the sense of modern hermeneutics -- i.e., the entering-in to the same time and the same meaning -- is to take place. . . .
Real advances in Christology, therefore, can never come merely as a result of the theology of the schools, and that includes the modern theology as we find it in critical exegesis, in the history of doctrine and in an anthropology oriented toward the human sciences, etc. All this is important, as important as schools are. But it is insufficient. It must be complemented by the theology of the saints, which is theology from experience. All real progress in theological understanding has its origin in the eye of love and in its faculty of beholding.
Cardinal Ratzinger - Behold The Pierced One (Ignatius Press, 1986) [pp. 25-27].