For Christians, the "Word of Life " is both human and divine : Christ is true God and true man. Theology experiences a constant tension as it mustn't sacrifice either one of the two aspects : in fact, it has to take into account the contribution of the human and natural sciences without losing its own specificity. The original place of theology would be the new and everlasting covenant, into which God entered with his people in Christ: all human reality finds its due place in it, moving towards its eschatological perfection. Thus theology is rooted in spirituality as the experience of the covenant, of which it deepens the knowledge as a continuous reasoning moving around the two poles that are in constant relation : God and his people. Dedicated to the relationship spirituality has respectively with the Bible, dogma, eschatology, literature and sciences, the five parts of this thesis explore this elliptical movement of theological reasoning and pay special attention to interdisciplinary questions