The Augustinian conception of faith – according to which faith and belief precede knowledge and understanding – appears to entail an epistemic violation. For Augustine, faith is exercised when a testimonial report that P is believed on the basis of that report. This reconfigures the factors involved in assessing whether what is believed on faith is believed rationally. The specific goal of this article is, however, to determine whether believing specifically Christian testimony – and, thus, faith – is rational. Jonathan Adler identifies six forms of background evidence that constitute epistemic reasons for believing testimony. At least five of them appear to be fulfilled for Augustine in the case of believing Christian testimony. Thus, Augustinian faith is supported by epistemic reasons, and should be considered rational.