What Protestants deny: the perfection of the law strictly taken
Thesis XXXVIII. The one thing Protestants mean to deny in this question, then, is that believers renewed by Christ's Spirit can fulfil the law with the whole perfection that the law, strictly taken, demands of man.
The law is taken strictly when it is judged by its first institution: as it was given to the first man and contained the first covenant made with him, by keeping which he was to look for unending and blessed life from God's goodness and justice together.
Taken in that way, the law demanded of man a perpetual obedience, broken by no sins and darkened by no defects or flaws, in which he would submit himself to God's will with the utmost readiness, with no struggle or resistance of the inner affections, in absolutely everything and without exception. This was the obedience our first parents could give God in the state of innocence, and were actually bound to give, so that they might remain in that blessed state and at last enjoy eternal happiness with God.
Latin
XXXVIII. Id solum igitur in hac quaestione Protestantes negare intendunt, fideles per Christi spiritum renovatos legem implere posse, secundum totam illam perfectionem, quam lex rigide sumpta, ab homine exigit. Porro lex rigide sumitur quum aestimatur ex prima sua institutione, & spectatur quatenus primo homini lata fuit, & continet primum illud foedus cum homine initum, ex cujus observatione perennem & beatam vitam, a Dei bonitate & justitia simul expectare debebat. Lex autem sic considerata exigebat ab homine perpetuam obedientiam, nullis peccatis interruptam, nec ullis defectibus, & naevis obscuratam, & per quam homo cum summa alacritate, absque ulla pugna, vel renitentia affectuum internorum, in omnibus omnino, sine exceptione, sese voluntati divinae submitteret. Qualem, scilicet, obedientiam primi nostri parentes, in statu innocentiae, Deo exhibere poterant, & exhibere reapse tenebantur, ut in beato illo statu manerent, & tandem aeterna cum Deo felicitate fruerentur.