I have chosen “spirituality” to characterize this chapter, because in recent decades the word has become the designation for the investigation of the lived experience of Christian faith. Spirituality is rooted in the New Testament texts that speak about living in “the Spirit of Jesus.” The noun occurs in roughly the modern sense as early as around 400 CE,1 and was widely used in the Middle Ages.2 Spiritualitas was employed by Catholic authors in the Reformation era. Protestants knew the term, but shied away from it, preferring to speak of piety and active faith.

The notion of a God who hides himself, either because that is a fundamental characteristic of the divine nature, or because God chooses to do so in relation to human attempts to know him, is widespread in many religious traditions. In the history of Christian theology this hiddenness has often been expressed as “apophatic theology” (the Greek apophasis literally means “unsaying”). For Christians the contention that at least in this life the mystery of God is better known by not-knowing than by knowing has roots in the Hebrew bible/Old Testament, as well as the New Testament, especially in those texts that speak of God's hiddenness. “Truly, you are a God who hides himself, O God of Israel, the Savior,” as Isaiah proclaims (Isa. 45:15). Though there is disagreement in the Hebrew Bible about whether God can ever really be seen, with some texts affirming the possibility (e.g. Gen. 32:30; Isa. 6:5), while others deny it (e.g. Exod. 33:20), there is no question in the New Testament about the radical invisibility of the Father. John's prologue says, “No one has ever seen God. It is God the only Son, who is close to the Father's heart, who has made him known” (John 1:18). The deutero-Pauline 1 Timothy is equally emphatic: “It is he alone who has immortality and dwells in unapproachable light, whom no one has ever seen or can see” (1 Tim. 6:16).

In his Sermo de diversis 121 Bernard of Clairvaux told his monks: ‘We are in the school of Christ (In schola Christi sumus), and there we learn two teachings: the one that the one true Master teaches us himself, that is, love; and the other through his ministers, that is, fear.’ The appeal to being in the ‘school of Christ’ was a mark of the self-identity of the Cistercian Order. Manifested in the abbot of Clairvaux, and also illustrated by three other major early Cistercian theologians influenced by him (William of Saint Thierry, Aelred of Rievaulx and Isaac of Stella), the ‘great miracle’, as Bernard put it, of the success of the Cistercians made a lasting impact on the medieval world. The institutional, political and cultural roles of the Cistercians are presented in other essays in this volume; here I will concentrate on their spiritual theology during the fifty years between c. 1120 and 1170. However much scholars continue to study the Cistercian Order, if the early Cistercians still reach a wide audience, it is fair to say it is largely because of their spiritual teaching, what they learned ‘in the school of Christ’.

The goal of learning in Christ’s school was not restricted to monastics. Bernard and his confreres believed that all the baptised are called to deeper knowledge and more intimate contact with God, even to the embrace of the Divine Word. In SC 83.1 Bernard says that all Christians are called to marriage with the Word, though monastics have a privileged highway to the goal. Although the White Monks were the virtuosi of the religious life, they felt an obligation to speak, both to other monks and (as history has shown) to non-monastics.

Although union language is not the only way of understanding how to attain some form of direct contact with God in this life, it has played a central role in the history of Christian mysticism. The notion that a human being can become one with a god or gods seems to depend on how one views divinity. When the gods are conceived of as stronger beings within the world system, the boundaries between the divine and the human realm are porous, allowing for various kinds of intermingling of superior and inferior beings. The emergence of belief in a single divine source of all things, a transcendent God or Supreme Principle, might seem to preclude the possibility of uniting with that principle. In the face of such transcendence, the proper response of humans should be worship, not desire for communion. Yet paradoxically, the growth of a strong sense of the difference between the one God and the limited world of creatures seems to have encouraged, rather than suppressed, desire to become one with God.

In the wake of the critique of the Olympian gods by Greek philosophers, uniting with the source of all things took on an increasingly important role in Greek philosophical religion. Many of the issues involved in union with the Supreme God were explored by Greek philosophers between ca. 300 BCE and 300 CE. The richest development is found in Plotinus (205–70 CE), whose Enneads set forth a sophisticated doctrine of attaining indistinct union, not only with ultimate existence, or Intellect, but even with the One hidden beyond the realm of all visible and invisible reality. Plotinus’s view of such “oneing” (henôsis) is, at times, expressed in personal terms: “But there is our true love, with whom we also can be united, having a part in him and truly possessing him, not in the flesh from outside. But ‘whoever has seen, knows what I am saying,’ that the soul then has another life and draws near, and has already come near and has a part in him.”

The mid-thirteenth-century German Franciscan David of Augsburg wrote one of the most popular handbooks of spiritual guidance of the late Middle Ages, whose title, The Composition of the Interior and Exterior Man according to the Triple State of Beginners, Proficient and Perfect, demonstrates its traditional approach. David expressed concern about the emphasis on visions and ecstatic experiences typical of many late medieval mystics, in part because these authors seemed to blur the distinction between interior experience and external sensation. At one point he singles out erotic visions of kissing and embracing that could even involve ‘being caressed by other less decent deeds and acts, so that just as the interior spirit is consoled by Christ or Mary, so too the exterior flesh is caressed in a physical way and carnally consoled by a sensation of delight fitted to it’. David is a witness to aspects of late medieval mysticism that seem to challenge the traditional distinction between external, bodily sensation and a separate set of interior, spiritual senses seen as organs of affective intentionality directed to God and the heavenly world.

The evolution of the category of spiritual sensation is long and varied, as the chapters of this volume demonstrate. To what extent did at least some late medieval mystics present teachings on perceiving God that tended to undermine, or negate, the distinction between inner and outer sensation, so that encountering the divine was presented as perceived in a corporeo-spiritual totality? Any adequate answer to this question would need a book, not a single chapter, to investigate the evidence. What follows is only a sounding in the capacious sea of late medieval mystical views on the role of sensation, inner and outer, in the path to God. To gain some sense of the teaching of some mystics in this domain, it is helpful to keep in mind a series of questions. First, what kind of language does the mystic use for describing how God is perceived? Second, does this language involve an explicit or implicit distinction between inner and outer sensation? If the distinction is explicit, does this mean that the spiritual senses are to be conceived of as a second set of senses, primarily as ways of describing interior cognition? Third, how does the mystic relate the various forms of sensation (inner and outer, or both together)? Is there, for example, a distinct form of knowing ascribed to each form of sensation? Is there a prioritizing of the senses? Finally (and this was increasingly important in the late Middle Ages), is there a discussion of how to discern the difference between true and false perceptions of God? To pursue each of these questions, even with regard to only a few mystics, would be a large task. My observations here will begin to sketch out something of this large terrain. Despite many helpful studies, we are still at the beginning of in-depth consideration of this central theme in the history of mysticism.

Vere tu es Deus absconditus – ‘Truly, you are a God who hidest thyself.’ In commenting on this verse from Isaiah 45:15 in his exegesis of the book, Martin Luther drew a parallel between the prophet's time and his own. The divine promise of restoration to Jerusalem, despite the trials of Isaiah's era, led the seer to exclaim that God's ways were beyond the power of reason, ‘The flesh sees nothing and concludes: Nothing produces nothing.’ But the eyes of faith see differently. ‘So today’, Luther continues, ‘we see in the Word the progress of the Church of God against the force and schemes of all tyrants. Since faith is the conviction of things not seen, the opposite must appear to be the case.’

Throughout his later Lectures on Genesis (1535–45) the reformer often employs the theme of divine hiddenness, citing the Isaian text in four of these discussions. In order to grasp the meaning of these and other passages, it is useful to note that Luther seems to have distinguished between two forms of God's hiddenness: God's hiding of himself sub contrariis, that is, under contrary signs; and God's hiding of himself in the dark mystery of predestination.

The first hiddenness, cloaking sub contrariis, shows how the tribulations endured by the patriarchs, so often in conflict with the promises God had made to them, provide the model for us, their heirs in belief.