Thesis XIII. Again, 'the righteousness of the law is fulfilled in us' and 'we fulfil the law and its righteousness' seem to say exactly the same thing. Now the apostle teaches that Christ came into this world so that the law's righteousness would be fulfilled in us, who live by the Spirit and not by the flesh.
'What the law could not do,' he says in Romans 8, 'because the flesh made it weak, God did by sending his own Son in the likeness of sinful flesh, and for sin: he condemned sin in the flesh, so that the justification, or righteousness, of the law would be fulfilled in us, whose walk follows the Spirit and not the flesh.'
Latin
XIII. Praeterea justitiam legis in nobis impleri, & nos legem & ejus justitiam implere eodem plane recidere videntur. Jam vero docet Apostolus Christum in hunc mundum venisse ut justitia legis impleretur in nobis, qui non ambulamus secundum carnem, sed secundum spiritum. Nam, inquit, quod erat impossibile legi, quia per carnem infirma erat, Deus filium suum mittens, in similitudinem carnis peccati, & de peccato, damnavit peccatum in carne, ut justificatio, sive justitia legis impleretur in nobis, qui non ambulamus secundum carnem, sed secundum spiritum. Rom. 8.