Body and soul do not make conflict natural: right order subjects the body's leanings to the soul
It does not follow, from man's being made of an earthly body and a spiritual soul, that the conflict of sense and appetite with reason is natural in him, or that such conflict and rebellion can only be removed by a supernatural gift.
Man does naturally have two inclinations, one toward earthly good because he has a body, the other toward spiritual good because he has an intelligent soul. But as the soul far surpasses its body, so a rightly formed nature requires that the body's impulses and inclinations be subject to the soul's commands, and so that appetite obey reason. Where it is otherwise, nature is plainly out of order.
Latin
LVIII. Neque ex eo quod homo constat corpore terreno & anima spirituali, sequitur in eo naturalem esse pugnam sensus & appetitus adversus rationem: adeoque talem pugnam atque rebellionem non posse tolli, nisi per donum supernaturale. Nam naturalis quidem est homini duplex inclinatio, una erga bonum terrenum, quatenus corporeus est, altera vero erga bonum spirituale, quatenus praeditus est anima intelligente: sed quemadmodum anima suo corpore longe praestantior est, ita quoque naturae recte constitutae convenit, ut corporis motus & inclinationes animae Imperiis & jussibus subjiciantur, & sic appetitus rationi pareat. Quum vero res aliter se habet, in eo apparet quaedam naturae deordinatio.