The article deals with some linguistic aspects of the Peter Trnovsky's sermons (1631) as they are reflected in various linguistic planes. In particular, the paper aims to clarify the lingual difference between these sermons and the other relics of a religious nature. The sermons are written in a relatively good cultural, north-west-middle type Slovak language with the numerous components from the Czech language, even they are not so appropriate in the Czech language. The fact that the author was a member of the Protestant Church is interesting, because he was supposed to use Bible language (the language of the Kralicka Bible) while he was doing his sermons. However, all the components typical for cultural language of the Slovak ethnic group are sufficiently used there.