One of the key texts in the discussion of Aquinas and the primacy of Scripture is as follows:
"Formale autem obiectum fidei est veritas prima secundum quod manifestatur in Scripturis sacris et doctrina Ecclesiae [quae procedit ex veritate prima]*. Unde quicumque non inhaeret, sicut infallibili et divinae regulae, doctrinae Ecclesiae, quae procedit ex veritate prima in Scripturis sacris manifestata, ille non habet habitum fidei, sed ea quae sunt fidei alio modo tenet quam per fidem."
* The bracketed material is found in the older texts (example) but is not found in some of the more modern texts (example) The translations below all include the phrase in the translation.
"Now the formal object of faith is the First Truth, as manifested in Holy Writ and the teaching of the Church, which proceeds from the First Truth. Consequently whoever does not adhere, as to an infallible and Divine rule, to the teaching of the Church, which proceeds from the First Truth manifested in Holy Writ, has not the habit of faith, but holds that which is of faith otherwise than by faith." (source - translation of Summa by "Fathers of the English Dominican Province")
"But the formal object of faith is primal truth as manifested in the Holy Scriptures, and in the teaching of the Church which proceeds from the primal verity manifested in those Holy Scriptures. Hence he who does not adhere to the doctrine of the Church as an infallible and Divine rule, has not the habit of faith, and if he hold anything which agrees with articles of the faith, he does not hold it through faith, but in some other way." (source - translation/paraphrase by John J. Elmendorf, S.T.D. for his "Elements of Moral Theology" based on the Summa Theologica)
"The formal object of faith is primary truth, as it is shown forth in the holy Scriptures, and in the teaching of the Church, which proceeds from the fountainhead of truth. It follows, therefore, that he who does not adhere, as to an infallible divine rule, to the teaching of the Church, which proceeds from the primary truth manifested in the holy Scriptures, possesses not the habit of faith; but matters of faith he holds otherwise than true faith." (source - in a translation of Pope Leo XIII quoting the passage)
"The formal object of faith is the Supreme Truth in so far as revealed in the Holy Scripture and in that doctrine of the Church which proceeds from the Supreme Truth. Hence if anyone does not hold to the doctrine of the Church as to an infallible and divine rule, . . . he does not possess the virtue of faith." (source - Catholic Encyclopedia entry on fundamental articles ellipsis that avoids reference to Scripture in original)
Since this is just intended as a reference to clarify, I won't include any argument here. I simply note that one should be careful about how one parses the English language translation (any of the translations) to avoid doing damage to the Latin original.