Chapter 32 — Part III: The Decalogue — The Ninth and Tenth Commandments
Section 7. Nor is this the only lesson of instruction which we derive from these Commandments. They also teach us that the divine law is to be observed not only by the external performance of duties, but also by the internal concurrence of the heart. Between divine and human laws, then, there is this difference, that human laws are fulfilled by an external compliance alone, whereas the laws of God, since He reads the heart, require purity of heart, sincere and undefiled integrity of soul.