Whereas Richard Swinburne has tried to make a case for the rationality of Christian revelation, this article argues for the rationality of early Christian discourse. Early Christian texts display a type of “formal” rationality that is not an attribute of Christian revelation, intending authors, or historical contexts, but rather is a property of the discursive series to which they belong. Early Christian texts could come into existence only by achieving a relational coexistence with other, previously existing, non-Christian texts within a shared associative discursive series. Such an addition of a Christian text to a discursive series was always governed by the shared “rules” of coherence of the series itself. As a starting point for elucidating these “rules” of coherence, this article examines the structures of social grouping, social interaction, and social values as they were reproduced in the linguistic categories of Hellenistic Greek. This article further argues that the emergence of biblical texts within their respective discursive series occurred according to two strategies, synchronic and diachronic emergence. Synchronic emergence involves the addition of texts to a discursive series in such a way that the “rules” of the series are instantiated without significant alteration. In contrast, the term diachronic emergence designates the addition of texts to a series whereby the “rules” are instantiated in a novel or unexpected manner. In both cases, the emergence of early Christian texts is a function of formal rational processes.