AbstractNgaka (the indigenous doctor and healer among Tswana speaking people) represented the spiritual priest among the Batswana and hence a great challenge to missionaries of colonial times, whose agenda was to sell a different form of spirituality. That the modern colonial framework dismissed all other forms of spiritual knowledge(s), situated the ngaka and bongaka (the practice of ngaka) at the centre of the colonial missionary displeasure. This article traces and analyses Robert Moffat's rewriting of the concepts of ngaka and bongaka in his 1842 monumental volume. It analyses Moffat's encounter with the ngaka, his characterisation of the ngaka and his efforts to translate the ngaka from a central social welfare figure among the Batswana to a marginal, if not an outright evil, pretender. The article also traces the resistance Moffat encountered in this specific endeavour. It also examines how the Batswana began to translate Moffat and his books (the Bible) into their own spiritual categories by regarding him as ngaka and referring to his books (the Bible) as bola (the divination set).