Zacharias said to the angel, "How can I be sure of this? For I am an old man, and my wife is well advanced in years."
At the same time, we ought to know that Zacharias was not so unbelieving as to turn aside wholly from the faith; for there is a general faith which embraces the promise of eternal salvation and the testimony of a free adoption. On the other hand, when God has once received us into favor, he gives us many special promises, — that he will feed us, will deliver us from dangers, will vindicate our reputation, will protect our life; — and so there is a special faith which answers particularly to each of these promises. Thus, it will sometimes happen, that one who trusts in God for the pardon of his sins, and for salvation, will waver on some point, — will be too much alarmed by the dread of death, too solicitous about daily food, or too anxious about his plans. Such was the unbelief of Zacharias; for while he held the root and foundation of faith, he hesitated only on one point, whether God would give to him a son. Let us know, therefore, that those who are perplexed or disturbed by weakness on some particular occasion do not entirely depart or fall off from the faith, and that, though the branches of faith are agitated by various tempests, it does not give way at the root. Besides, nothing was farther from the intention of Zacharias than to call in question the truth of a divine promise; but while he was convinced generally that God is faithful, he was cunningly drawn by the craft and wiles of Satan to draw a wicked distinction. It is all the more necessary for us to keep diligent watch: for which of us shall be secure against the snares of the devil, when we learn that a man so eminently holy, who had all his life maintained strict watchfulness over himself, was overtaken by them? 