There are three different distinct kinds of obedience. For either from fear of punishment we avoid evil and are servilely disposed; or looking to the gain of a reward we perform what is commanded, like to mercenaries; or we obey the law for the sake of good itself and our love to Him who gave it, and so savour of the mind of children.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).