For skill in theology is the habit of the whole person, by which he is brought to possess God and to act according to his will and for his glory. For this reason the whole person and all his parts are said to be sanctified (1 Thess. 5:23), but especially the will, which is the principium that commands all spiritual actions.

PETRUS VAN MASTRICHT, THEORETICAL-PRACTICAL THEOLOGY, VOLUME 1: PROLEGOMENA, 249.