Chapter 15 — Part II: The Sacraments — Introduction on the Sacraments in General
Section 27. Another reason is because the mind yields a reluctant assent to promises. Hence, from the beginning of the world, God was accustomed to indicate, and usually in words, that which He had resolved to do; but sometimes, when designing to execute something, the magnitude of which might weaken a belief in its accomplishment, He added to words other signs, which sometimes appeared miraculous. When, for instance, God sent Moses to deliver the people of Israel, and Moses, distrusting the help even of God who had commissioned him, feared that the burden imposed was heavier than he could bear, or that the people would not heed his message, the Lord confirmed His promise by a great variety of signs. As, then, in the Old Law, God ordained that every important promise should be confirmed by certain signs, so in the New Law, Christ our Saviour, when He promised pardon of sin, divine grace, the communication of the Holy Spirit, instituted certain visible and sensible signs by which He might oblige Himself, as it were, by pledges, and make it impossible to doubt that He would be true to His promises.