The subject of the article is the theme of Lucifer in Lilja, a poetic Icelandic biblical paraphrase dating from the first half of the 14th century. When analyzing Lucifer stanzas, attention is paid to the forms of speech of the author, their communicative properties and distribution. Attention to the sources of the monologue is determined by specificity of its structure and by peculiarities of the internal monologue as a form of speech. One thesis is that the context of St. Anselm’s speculative theology supports an interpretation of the monologue, which corresponds to the main idea of all Lucifer stanzas in Lilja. The article contains two sections, within the framework of which the following tasks are solved: In the first section, the forms of speech in Lucifer stanzas are compared with the forms of speech in the songs of the Poetic Edda; the purpose of the comparative analysis is to clarify relationship of Icelandic biblical paraphrase to the poetic traditions of Iceland. The second section of the article examines Lucifer’s monologue and its sources; here the structure of the monologue is considered and its meaning is clarified in the context of Lucifer stanzas on the one hand and the works of St. Anselm on the other. Results of the analysis are summarized in the Conclusion. The main method of work is comparative textual analysis from the standpoint of historical poetics.