Bellarmine: original righteousness a golden bridle; natural as from birth and as suiting nature, not as flowing from its principles
Next he says that at the beginning of creation divine providence, to remedy this sickness or weakness of human nature arising from the condition of matter, gave man a remarkable gift, original righteousness. By it, as by a golden bridle, the lower part was kept easily subject to the higher, and the higher to God.
The flesh was so subject to the spirit that it could not be moved against the spirit's will or rebel against it unless the spirit itself rebelled against God, though it was in the spirit's power to rebel against God or not.
From this he concludes that the first man's righteousness was natural in the sense that whatever one has from birth is natural, and in the sense that what suits nature is natural; but it was not natural in the sense in which natural is distinguished from supernatural and means what flows from nature's principles.
Latin
X. Deinde dicit divinam providentiam initio creationis, ut remedium adhiberet huic morbo seu languori naturae humanae, qui ex conditione materiae oriebatur, addidisse homini donum quoddam insigne, justitiam videlicet Originalem, qua veluti aureo quodam fraeno pars inferior parti superiori, & pars superior Deo facile subjecta contineretur. Sic autem subjectam carnem spiritui, ut non posset ipso invito moveri, neque ei rebellis fieri, nisi ipse fieret rebellis Deo; in potestate tamen spiritus fuisse Deo rebellem fieri, & non fieri. Unde colligit primi hominis justitiam naturalem quidem fuisse, quatenus naturale dicitur id omne quod habetur a nativitate, & quatenus naturale dicitur id quod est naturae consentaneum, sed non fuisse naturalem, quatenus naturale distinguitur a supernaturali, & significat id quod fluit ex principiis naturae.