"error concerning creatures . . . spills over into false opinion about God".

"the opinion is false of those who asserted that it made no difference to the truth of the faith what anyone holds about creatures, so long as one thinks rightly about God. . . .  For error concerning creatures ... spills over into false opinion about God...."

"falsam esse quorundam sententiam qui dicebant nihil interesse ad fidei veritatem quid de creaturis quisque sentiret, dummodo circa Deum recte sentiatur, ... nam error circa creaturas redundat in falsam de Deo sententiam...."

     St. Thomas Aquinas, Summa contra Gentiles II.iii.6, citing Augustine, On the origin of the soul IV.4, as trans. James F. Anderson.  Latin from Corpus Thomisticum.  Cited, tellingly, by Emmanuel Perrier O.P., in his lecture "Thomas Aquinas on creation and nature" (which opens with a reference to four de-natur-ations of secularism), Thomistic Institute Angelicum, 5 October 2019, at 25:10 and following:

To hold on[to] natural law ethics is not only legitimate on philosophical grounds; it is also a theological necessity for Christians....  Many Catholics today, influenced by the general movement of de-natur-ation, share the opinion that we should spare ourselves the burden of defending natural law ethics, and ... focus instead on preaching the Gospel.  Faith in Jesus Christ seems enough.  But besides the fact that it would lead, it would be a direct path to a religious kind of de-natur-ation like Qur'an, what would be our faith in Christ if it were no more the faith in Jesus Christ our Lord?  To have faith in Jesus Christ our Lord we need natural law ethics because Jesus Christ is our Lord in governing the universe, that is, every nature towards its end.

"a sober person does not take less pleasure in food taken in moderation than the glutton, but his concupiscence reposes less in such pleasures."

"Beasts are without reason. In this way man becomes, as it were, like them in coition, because he cannot moderate concupiscence. In the state of innocence nothing of this kind would have happened that was not regulated by reason, not because delight of sense was less, as some say (rather indeed would sensible delight have been the greater in proportion to [(fuisset enim tanto maior delectatio sensibilis, quanto)] the greater purity of nature and the greater sensibility of the body), but because the force of concupiscence would not have so inordinately thrown itself into [(non ita inordinate se effudisset super)] such pleasure, being curbed by reason, whose place it is not to lessen sensual pleasure, but to prevent the force of concupiscence from cleaving to it immoderately [(ad quam non pertinet ut sit minor delectatio in sensu, sed ut vis concupiscibilis non immoderate delectationi inhaereat)]. By 'immoderately' I mean going beyond the bounds of reason, as a sober person does not take less pleasure in food taken in moderation than the glutton, but his concupiscence lingers less in such pleasures [(sobrius in cibo moderate assumpto non minorem habet delectationem quam gulosus; sed minus eius concupiscibilis super huiusmodi delectatione requiescit)]. This is what Augustine means by the words quoted, which do not exclude intensity of pleasure [(magnitudinem delectationis)] from the state of innocence, but ardor of desire and restlessness of the mind [(ardorem libidinis et inquietudinem animi)]."

     St. Thomas Aquinas, ST I.98.2.ad 3, trans. FEDP.  As trans. more freely by Edmund Hill on pp. 157 and 159 of vol. 13 of the Blackfriars edition published in 1964:

Animals lack reason.  So what makes man like the animals in copulation is the inability of reason to temper the pleasure of copulation and the heat of desire.  But in the state of innocence there would have been nothing of this sort that was not tempered by reason.  Not that the pleasurable sensation would have been any the less intense, as some [(Bonaventure, Alexander of Hales)] say, for the pleasure of sense would have been all the greater, given the purity of man's nature and sensibility of his body.  But the pleasure urge would not have squandered itself in so disorderly a fashion on this sort of pleasure when it was ruled by reason.  It is not demanded by this empire of reason that the pleasurable sensation should be any the less, but that the pleasure urge should not clutch at the pleasure in an immoderate fashion; and by 'immoderate' I mean going beyond the measure of reason.  Thus a sober man has no less pleasure in food taken moderately than a greedy man; but his pleasure urge does not wallow so much in this sort of pleasure.  And this is the bearing of Augustine's words, which do not exclude intensity of pleasure from the state of innocence, but impetuous lust and disturbance of mind.