Michel Barnes has identified the “X from X” formulation (e.g., “Light from Light,” “God from God”) as a traditional expression of causality in early Christian theology, but how it was it employed to speak of consubstantiality varied. A close reading of the contemporary documents reveals the nuanced manner in which the phrasing could be used or rejected by both pro-Nicenes and their opponents depending on how it was qualified. For example, Arius rejected the phrasing “λύχνον ἀπὸ λύχνου” because he believed it diminished the Father (Fides Nicaenae Synodi 11.3; 6.3). In contrast, Valens, Ursacius, and colleagues happily utilized this structure to label the Son “Filium…ex Patre, Deum ex Deo, lumen ex lumine” in the Sirmium Manifesto. But their opponent the pro-Nicene Phoebadius of Agen believed their use was a duplicitous means of separating the Son from the Father and instead proposed a corrective employing John 14:10, reflecting a shift in pro-Nicene argumentation (Contra Arianos 2.4). And his confrère Gregory of Elvira accepted this “X from X” provided that the preposition employed was one believed to ensure consubstantiality between Father and Son (De fide Orthodoxa 53); this approach becomes standard for Ambrose and his Latin peers as well.
Certainly the meaning of such phrasing for each author depended upon how it was conditioned by the larger theological context. The aim of this presentation is to identify the key components differentiating their use of this grammatical structure and how it represented their view on the relationship of Father and Son. Texts from these figures will be presented in order to clarify the theological concerns of each and the trajectories they proposed in employing this language (if they did at all). Further, this paper assesses how these different treatments informed later use of this phrasing, especially in the West.