To Florus 3.167
In that first work I had already argued about fleshly desire or pleasure, also called lust, implanted in the sexes for the reproductive activity of generation. I showed that it is nothing other than one of the body’s instruments, implanted alike in rational and irrational beings and belonging to God’s work, since he equipped our flesh with sensations. Yet Augustine attacks it fiercely, calling it evil—that is, natural sin and the parent of every sin. He tries to persuade us chiefly from its shame, and mocks me for being ashamed to name it directly.
Latin
Et quamvis iam pro concupiscentia vel voluptate carnis, quae etiam libido dicitur, quae sexibus ob virilitatem propagationis inserta est, primo illo opusculo eatenus disputaverim, ut docerem illam nihil aliud esse quam unam de instrumentis corporis rationabilibus et irrationabilibus aeque inditam ad Dei operam pertinentem, qui carnem nostram in sensibus affecisset, tamen, quia ei vehementer Augustinus incumbit eamque dicit malam, id est peccatum esse naturale atque omnium peccatorum parentem, quod pudore eius potissimum persuadere conatur meque irridet, qui eam erubescam nominare directim.