This edition of St. Cyril of Alexandria's Commentary on the Book of Exodus: First Discourse is intended to serve as an introduction to the complexity of Greek forms of diction as they develop in Christian literature in the first four centuries of the Christian Era. The main focus is the translation (for the first time in English) of the Commentary on the Birth of Moses¿-¿First Discourse¿-¿composed by St. Cyril of Alexandria in the fourth century ad. A list of the basic vocabulary used by Cyril is included. This book is the second in a series of publications of translation and commentary of texts from the early Christian period, which present challenges in their grammatical construction, illustrate the development of the Greek language from the Classical Attic to Modern Greek, and can be used as study guides for a diachronic approach of Greek Literature. These publications are also intended to be used as textbooks for advanced studies in Ancient, Early Christian and Byzantine Greek since they exhibit a great variety of forms of diction, an impressive wealth of vocabulary and they illustrate the complexity and occasionally the difficulty of expression when the authors regress into archaic styles in order to impress their audiences. This is the reason why a diachronic and interdisciplinary approached has been adopted in the Introduction, tracing the development of the Greek language from the Koine to Modern Greek and comparing it to its origins in Classical Attic.