The French Dominican scholar, Giles Emery, hits on a point I’ve been making a lot lately in his great work The Trinity in Aquinas (2004), namely, that Thomas Aquinas’ theological method was highly—to a remarkable degree—biblical, focused in particular on the literal historical sense. This is especially evident in his Summa Contra Gentiles (not to be confused with the “other” Summa!). Check this out. . . Among other things, he points out that in his Trinitarian treatise Thomas doesn’t cite Conciliar authorities in his primary treatment—his intent is to show that the Catholic faith, over and against the heretics (e.g., Sabellius, Arius, Photinus), preserves the teaching of Scripture.
Thomas’s method thus exploits all the resources of a literal reading on its own terms, particularly that of very frequent recourse context (circumstantia litterae, contextus litterae), and to words preceding or following the text in question, in order to provide the overall interpretation of a passage which makes up a whole. If necessary, Thomas gives several possible interpretations, explains the general sense of a mode of expression found throughout the Bible, or discusses a problem of textual criticism or of the Latin translation from the Greek. His reading of Scripture is of course theological and doctrinal, intended to bring out the dogmatic content of the wording. . .
Finally, it should be pointed out that with the exception of the question of the Filioque, Thomas at no point calls upon the authority of the Church, the Councils, or the Fathers. Throughout all these pages, Scripture provides its own interpretation. This methodological characteristic evidently does not exclude the authority of the Church, as is clear from the numerous references to the ‘Catholic faith’ which implicitly point to Church authority. But what Thomas wants to demonstrate is the conformity of the Catholic faith to the teachings of Scripture. The specific point he intends to make is that of the Catholic Church being taught by the documents of Scripture (Sacrae Scripturae documentis Ecclesia catholica docta). This clear affirmation of the primacy of Scripture, both in practice and in theory, should be understood first and foremost in the light of the foundations of Trinitarian theology (only Scripture provides us with knowledge of the Trinity which is received in faith) and because of the acknowledged significance of heresies concerning the Trinity. There is no point in employing arguments relying on the authority of the Church when faced with doctrines which reject this authority: The debate should rather be located within a context recognized by the interlocutor as being authoritative. The heresies being addressed by Thomas, however, and countered through the Catholic faith, claim to have their roots in Scripture. We should note, though, that the Fathers and the Councils (especially those of Nicea and Constantinople I) are never absent from the background discussion, and the Councils’ deliberations on matters of faith are actually at the heart of Thomas’s writing. It would seem appropriate at this point to suggest that Thomas is here setting out to provide his own, personal account of Patristic and Counciliar writings, based on scriptural and doctrinal sources. If therefore the heresies are dispelled, it is because the doctrines involved are not what Scripture teaches. This is an excellent illustration, in the characteristic style of the Summa contra Gentiles, of Thomas’s habit of equating sacred doctrine (theology) with Holy Scripture.”
 The two expressions are referred to in SCG IV, ch. 8 (#3430).
 See for example SCG IV, ch. 8 (#3431; #3433; #3435).
 SCG IV, ch. 8 (#3436); ch. 23 (#3597).
 For example in the case of exclusive expressions (exclusive mentions of whichever divine person), in SCG IV, ch. 8 (#3428–29); ch. 23 (#3596); ch. 25 (#3622); or for the interpretation of divine knowledge in the sense of ‘making known,’ ch. 8 (#3435); ch. 23 (#3600).
 See SCG IV, ch. 17 (#3527), regarding Phil 3:3; we also find a reference to Hebrew in ch. 7, regarding Jer 23:6 (#3408).
 SCG IV, ch. 7 (#3424).
 An implied reference to Pseudo-Dionysius in chapter 25 (#3621) recalls this.
 This principle governing discussion with non-Catholics is set out in an especially detailed manner in the De rationibus fidei, Prologue. It also provides the explanation for Thomas’s references to Councils of Antiquity in the discussion of the Filioque: such authorities were recognized by the Eastern Church.