This article argues that several biblical texts, including some previously unrecognized ones, impelled the foundational apologetic argument of the first letter to Autolycus by Theophilus, the second-century bishop of Antioch. I focus here not only on biblical passages in Theophilus’s mental and social worlds that he may have consciously used and that appear in biblical indices in modern editions of Ad Autolycum, but also on previously unrecognized ones which, nonetheless, leave subtle traces, and which Theophilus may even have used unconsciously. To uncover the “literary echoes” of these passages, I exploit Hollander’s intertextual approach. This study can show how a sensitivity to literary echoes can produce deeper understanding of the formation of the strategy of Theophilus’s first apologetic letter, of his conformity to ancient ideals regarding the creative use of a classic corpus, and of functions of Scripture in his largely oral second-century community and in early Christianity more broadly.