The skill of living for God is not a natural power, one to which we are not taught but made; it is instead an acquired faculty, and therefore it certainly demands a rule to direct it, and in fact one that has been prescribed by God, as we taught just above. Over and above the life of Christ and one’s own conscience, we previously established that this rule is the Word of God, or Scripture. And as it is the norm for living, it is thus also a common complex of precepts and rules that apply to living. For this reason it is called the principium of theology. We will build our reflection on this point on the words from 2 Timothy 3:16–17

PETRUS VAN MASTRICHT, THEORETICAL-PRACTICAL THEOLOGY, VOLUME 1: PROLEGOMENA, 271.