Three requirements of true obedience
Thesis XXIII. To make this clearer, note that three things above all are needed for our obedience to be true and sincere. First, it must be given not only with the body and outward action but with the inner affection of the mind as well. Doing what the law commands profits nothing unless it springs from love of God and from zeal to carry out his will and advance his glory. Equally, a certain wish to obey God is not enough unless his commandments are actually carried out in deed when the situation calls for it.
Second, true obedience is not satisfied by keeping some of God's commandments while neglecting the rest. We must earnestly submit to every precept of the divine law and try to fulfil each one as occasions arise. Third, our obedience must be steady and lasting. Obeying God for a while is not enough; we have to persevere in obeying him to the end, in hard times as in good ones.
Latin
XXIII. Ut autem istud clarius innotescat, observandum est ad hoc, ut obedientia nostra vera & sincera sit, tria praecipue requiri. Primum est ut praestetur non tantum corpore & opere externo, sed interno quoque animi affectu. Neque enim quicquam prodest ea facere quae lex jubet, nisi id fiat ex Dei amore, & voluntatis illius implendae ac gloriae ejus promovendae studio. Ut nec satis est quendam affectum Deo obsequendi habere, nisi mandata ejus, quum res id postulat, ipso opere compleantur. Praeterea non sufficit ad veram obedientiam ut quaedam Dei mandata, reliquis neglectis, servemus: sed necesse est ut omnibus legis Divinae praeceptis nos serio subjiciamus, illaque, cum sese offert occasio, implere studeamus. Denique debet esse obedientia nostra constans & perseverans: Nec satis est Deo ad tempus obsequi, sed in ejus obsequio, tam per res adversas quam per res secundas, ad finem usque perseverandum est.