Introduction. The article characterizes the religious discourse of Father John of Kronstadt in the unity of argumentative and conceptual aspects, substantiates the hypothesis that the integrative description of discourse reveals the mechanism of interaction between language and thinking, both at the level of actualization of the concept and at the level of argumentation. The purpose of the article is to identify the linguistic argumentative potential of the discourse of “Lessons of Christian Life” through the three–part actualization of the concept of “Heart”. Materials and methods. The material for the article is a collection of sermons and teachings on church holidays “Lessons of Christian Life”. The work uses a set of analysis methods: continuous sampling, argumentative, conceptual, interpretive, discursive, semantic-stylistic. Research results, discussion. In the course of the analysis, we have established the main concept of the discourse under study – “Heart”, identified three levels of representation of the concept – conceptual, figurative, value. For each level of the concept, appropriate argumentative means are identified and described. Conclusion. The discourse-forming concept in the text under study is the concept of “Heart”, which is associated with the linguistic argumentative potential of the discourse of Father John of Kronstadt. Certain argumentative means correspond to each level of the concept. Affirmation of positive values through negation of negative values (argumentum a contrario) is a frequent technique in Father John’s reasoning. The linguistic argumentative potential is represented by various speech genres (good advice, call for mercy, warning, instruction, advice-instruction), in which the concept of “Heart” appears as a dominant component. A distinctive feature of the pathos of religious discourse is a different understanding of the concept of “conviction”: the act of suggestion is necessarily explicated as an intra-subject act, relevantly realized thanks to the concept of “Heart”.