Establishing the source of Ælfric's biblical quotations is often fraught with difficulty, and this is indeed the case when we examine his use of the Bible in DTA. To complicate matters, frustratingly we have no contemporary Latin text of the first twenty-nine chapters of Genesis with which to make comparisons. It is, moreover, a consistent feature of Ælfric's style that he deviates freely from known Vulgate versions, and sometimes from any known version. At any point, he may be quoting from memory, or from an intermediate source, or indeed both. In the Catholic Homilies, we can regularly see him giving biblical quotations from his patristic sources, often reflecting a pre-Hieronymian Old Latin tradition, rather than directly from the Vulgate text. In practice, diligent and conscientious monks such as Ælfric would have known substantial portions of the Bible by heart, but even allowing for the vagaries of memory, different schools may have used slightly differing forms of text. Ælfric was clearly aware of the existence of different textual traditions and variant readings, and it would not be surprising to see a gradation, in terms of fidelity to known Vulgate texts, from an avowed translation, as in the case of Ælfric's rendering of Genesis I–XXIV included in the collection known as the Old English Heptateuch, to the pedagogical use of scriptural texts in a more general educational work like DTA.

In the preface to his translation from Genesis, Ælfric famously set out his reservations about the whole principle of biblical translation, in particular his fear of putting difficult material into the hands of those incapable of fully understanding it, who could thus fall into error. The examples he gives there suggest that he was thinking not only of the laity. However, he also makes some asides on the mechanics of translation: