This paper explores the function of teachers' witnessing of faith in worldview education in the context of diversity in the classroom. Pollefeyt described three teaching roles for hermeneutical-communicative worldview education: moderator, specialist, and witness. These roles aim to support students in their personal worldview identity development. However, witnessing seems to be associated with the transmittal of a specific tradition. We explore Pollefeyt's intentions with witnessing and his didactical application. We deepen his perspective with Ricoeur's philosophical and biblical explorations of testimony which help to clarify witnessing and to position this didactical role in the interreligious educational space of vulnerability and hospitality. In closing, witnessing is related to the concepts of authenticity, moral agency, role model and self-disclosure to show its relationship to more general aspects of teaching.