"what pertains to faith is distinguished in two ways, for some are as such of the substance of faith, such that God is three and one, and the like, about which no one may licitly think otherwise. . . . Other things are only incidental to faith insofar as they are treated in Scripture, which faith holds to be promulgated under the dictation of the Holy Spirit, but which can be ignored by those who are not held to know scripture, such as many of the historical works. On such matters even the saints disagree, explaining scripture in different ways. Thus with respect to the beginning of the world something pertains to the substance of faith, namely that the world began to be by creation, and all the saints agree in this.
"But how and in what order this was done pertains to faith only incidentally insofar as it is treated in scripture, the truth of which the saints save in the different explanations they offer [(cujus veritatem diversa expositione sancti salvantes, diversa tradiderunt)]."
Thomas Aquinas, Super Sent., lib. 2 d. 12 q. 1 a. 2 co., trans. Ralph McInerny (Thomas Aquinas: selected writings, ed. and trans. with an introduction and notes by Ralph McInerny (London: Penguin Books, 1998), 91). The Latin is taken from the Parma edition of 1856, as reproduced in Corpus Thomisticum here: http://www.corpusthomisticum.org/snp2012.html#4546.