Necessary grace does not stop the sinner sinning freely
Thesis XXXVIII. Grace is wholly necessary if corrupt man is to do any good work, and without grace he can do nothing well and in conformity with God's law.
Yet in the Protestants' view this does not prevent man in that state from acting freely when he does evil, whether by committing what the law forbids or omitting what it commands; in doing so he exercises the native power of his free choice.
Latin
XXXVIII. Etsi vero gratia prorsus necessaria sit, ad hoc ut homo corruptus possit aliquod bonum opus facere, nec sine gratia valeat quicquam operari bene & divinae legi conformiter: id tamen non obstat, ex Protestantium sensu, quominus in eo statu homo, dum male agit, sive committendo ea quae lex prohibet, sive omittendo ea quae praecipit, id libere faciat, & vim nativam liberi sui arbitrii exerat.