Isaiah had experienced that sense of the numinous which has periodically descended upon men and women and filled them with fascination and dread. In his classic book The Idea of the Holy, Rudolf Otto described this fearful experience of transcendent reality as mysterium terribile et fascinans: it is terribile because it comes as a profound shock that severs us from the consolations of normality and fascinans because, paradoxically, it exerts an irresistible attraction. There is nothing rational about this overpowering experience, which Otto compares to that of music or the erotic: the emotions it engenders cannot adequately be expressed in words or concepts. Indeed, this sense of the Wholly Other cannot even be said to "exist" because it has no place in our normal scheme of reality.
— Karen Armstrong
Otto's *mysterium tremendum et fascinans* — Armstrong renders it *terribile*, which is exact enough — describes something the spiritual traditions have always half-known and half-concealed: the numinous does not arrive as comfort. It severs. The word Otto uses for what happens to ordinary reality is *tremendum*, and the severing is not metaphorical. The consolations of normality are exactly what get cut away, which means the numinous is not what spirituality typically promises when it markets itself as peace, integration, the higher self. It is closer to catastrophe than to arrival.
What makes this passage worth sitting with is the paradox Armstrong underscores — *terribile* and *fascinans* together, not in sequence. The soul does not first dread and then become attracted; it dreads and is drawn simultaneously, which means the attraction is not relief from the terror but runs straight through it. This is why Otto reaches for music and the erotic rather than theology: both pull hardest precisely where they wound. The Wholly Other, as a category, resists every attempt to domesticate it into a framework of growth or meaning-making — and that resistance is not a deficiency in the framework. It is the numinous doing exactly what the numinous does.
Karen Armstrong·A History of God·1993