Defects in the works of the godly are accidental; in the graceless, essential
Thesis XX. It is true that even the works of the godly and righteous, done through God's grace, have their own blemishes and defects. But those defects are only accidental and do not take away the essence of a good work. The defects that spoil the works of those without the grace of Christ are essential ones, and the very nature and essence of a good work cannot survive them. A work's goodness depends chiefly on the end it tends to and the principle it springs from.
Yet all the works of a man without the grace of Christ, as shown above, miss the true end, which is God's glory, and take their origin from a bad principle, earthly desire. That ruins a work that would otherwise be good in its kind. The works of the godly and righteous proceed from love of God and tend to his glory. Their only shortfall is that God's glory is not sought in them as purely as it should be, and the love of God they flow from is not as fervent as it ought to be.
So the works of the godly are good, imperfectly but truly. Whatever works are done by those who lack the grace of Christ, however brightly they shine in men's eyes, are really bad before God and do not keep the nature of a good work, though some are less bad than others.
Latin
XX. Verum est quidem etiam piorum & justorum opera per gratiam Dei facta suos quoque naevos & defectus habere; sed hi defectus sunt tantum accidentales, qui boni operis essentiam non tollunt. Qui vero vitiant opera eorum qui sunt Christi gratia destituti, sunt defectus essentiales, cum quibus salva manere non potest ipsa boni operis natura atque essentia. Siquidem operis bonitas praecipue pendet a fine in quem tendit, & a principio unde oritur. Sed hominis qui est gratiae Christi expers, opera omnia, ut supra ostendimus, & a vero fine aberrant, qui est Dei gloria; & a malo principio, cupiditate, scilicet, terrena originem ducunt: per quae opus alioqui ex suo genere bonum, omnino vitiatur. Piorum vero & justorum opera procedunt a Dei amore, & ad ejus gloriam tendunt, ac in eo solum deficiunt, quod nec in iis tam pure Dei gloria quaeritur, nec Dei amor unde fluunt tantum fervorem habet, quam par esset. Adeoque piorum opera imperfecte quidem sed vere bona sunt; eorum vero qui gratia Christi carent opera quaevis, ut ut in oculis hominum luceant, coram Deo revera mala sunt, nec boni operis naturam retinent: licet alia sint aliis minus mala.