Religious sermons play a very significant role in a pluralist setting like Nigeria, as organs of social, political and moral education. The fulfilment of these functions is partly contingent on the effective use of language. If the sermon-giver and his audience draw from the same pool of lexis, communication in the genre will not only be enhanced but its teaching and practice will also align, thereby bridging the gap between the two. It is to this end that this study attempts to identify the words most associated with Christian sermons in English, in Nigeria. To carry out this study, a corpus of present-day sermons in Nigeria was constructed and compared to a reference corpus of sermons from other parts of the world, in order to find out those lexical items which are characteristic of sermons, whether in terms of types, frequency or usage. The study reveals the role of textual context to be the definition of thematic focus because, although the sermon words in the two contexts manifest high similarity, their degrees of significance in the contexts differ substantially. Additionally, the findings reveal diversity, both in lexical choice and the discourse structure of sermons. However, in both contexts, the sermons demonstrate similarity in semantic grouping. So, for the teacher of English for religious purposes (ERP) and the user of English in church contexts, this work offers insights into the lexical world of sermons in Nigeria.