This article describes in what ways and within what genre horizons Protestant authors use mystical language. Mystical language seeks to activate the attentiveness and sensitivity of its recipients in order to open up an experience of God for them. Niels Hemmingsen, in his pastoral theology, combines the mystical pastoral ideal of antiquity with Melanchthon's anthropology and uses mystical language to problematize the disruptive demands on pastoral sensory faculties by the external world and to call the pastor back to his vocational experience. Johann Arndt, in his sermon on Mt 2, employs the allegorical technique of interpretation as permitted by Lutheran homiletics as a formative device to show directly to his hearers the sublimity and deliciousness of the Christian faith. Gottfried Arnold intertwines historiography and mystagogy: by compiling mystical foreign quotations with each other, he wants to guide the historically as well as mystically interested readers to unification with the divine, a concern that he sees rooted and realized in Luther's original theology. In this way, the texts shed light on a basic, indeed Protestant, quality principle of mystical language: its functionality.