What the law asked of the first man, and what the regenerate give
Thesis XV. That law required the first man to obey God with complete eagerness and readiness, without any sluggishness or reluctance. As long as he stayed upright he really could give God that kind of obedience, and he could not have fallen even slightly short of it without a fault that would have made him guilty before God's judgment.
How far the regenerate now are from that perfection, each one's own feelings and conscience bear witness. When they obey God's law and do good, they do it only with great difficulty. The corrupt desire that remains in them after they have received God's grace weighs them down with listlessness and sluggishness when they need to give themselves to worshipping God and to the other acts the law commands; and when evil must be avoided, it stirs up in them a leaning and inclination toward it.
That is why they follow the Holy Spirit's lead toward good only with difficulty, and tear themselves away from the lure of sin only with difficulty. So they do not flee evil or pursue good with the ardour, or from the pure zeal for God's glory, that unfallen man could have shown as the law required.
Their good works do conform to the law, then, but not to the strict exactness (ἀκρίβειαν) the law demands when measured by its original institution, the exactness to which man, before sin corrupted him, could and should have conformed his works.
Latin
XV. Nempe lex illa a primo homine postulabat, ut omni cum alacritate atque promptitudine, absque ullo torpore, sive renitentia Deo obsequeretur, & reapse primus homo, quamdiu integer mansit, tale obsequium Deo exhibere poterat: nec tantillum ab ea perfectione recessisset absque vitio & culpa, cujus se in Dei judicio reum constituisset. Quantum vero jam ab ea perfectione absint qui sunt per Christi gratiam renati, testatur cujusque eorum sensus & conscientia. Etenim quum legi divinae obediunt & bene operantur, id non faciunt sine magna difficultate. Prava concupiscentia, quae post acceptam Dei Gratiam in iis manet, quando divino cultui & aliis actibus lege praeceptis vacandum est, multum illis languoris & torporis injicit: quum vero mala vitanda sunt, propensionem & inclinationem in iis ad illa excitat. Unde fit ut in bonis aegre sequantur Spiritus sancti ductum, & in malis aegre avellantur ab illecebris peccatorum. Proindeque nec mala fugiunt, nec bona prosequuntur tanto cum ardore, atque ex tam puro Gloriae Dei zelo, quam lege exigente, homo integer manens id praestare potuisset. Et ita bona eorum opera legi quidem conformia sunt, sed tamen non juxta ἀκρίβειαν illam, quam lex ex prima sua institutione aestimata exigit, & secundum quam homo nondum peccato corruptus, opera sua legi conformare poterat & debebat.