and the other whenever you will. I say there is no sinner whose conduct does not show that his actions are perfectly in his own power. The thief waits for the night to carry on his trade; during the day he is honest enough. The greatest libertine knows how to behave himself in the presence of a high-born and virtuous female. {115} And even that vice which men say it is most difficult of all to restrain when once the habit is formed--profane swearing--you know how to restrain it when you will, for even the heaviest curser and swearer ceases from his oaths before the priest, or any other friend whom he greatly respects. Now, if you can stop cursing before the priest, why can you not before your wife and children? If you can be chaste in the presence of a virtuous female, why can you not be chaste everywhere? If you can be honest when the eye of man is on you, why can you not be honest when no eye sees you but that of God? But some one may say, there is a class of sins to which the remarks you have made do not apply, that is, sins of thought. You must admit that they are of such a nature that it is all but impossible not to commit them. No, I do not admit it. I acknowledge that sins of thought are more difficult to guard against than sins of action; but I do not acknowledge that it is impossible to guard against them. To prove this I have only to remind you that an evil thought is no sin until we give _consent_ to it. {116} To keep always free from evil thoughts may be impossible, because the imagination is in its nature so volatile, that but few men have it in control; but though it be not possible to restrain the imagination, it is always possible to restrain the will. In order for the will to consent to evil it is necessary both to _know_ and to _choose_, and therefore from the nature of the thing one can never fall into sin either inevitably or unawares. And besides, the will has a powerful ally in the conscience, whose province it is to keep us from sin and to reproach us when we do sin--so that it is scarcely possible, for one who habitually tries to keep free from mortal sin, to fall into it without his conscience giving a distinct and unmistakable report. And this is so certain that spiritual writers say that a person of good life and tender conscience, who is distressed with the uncertainty whether or no he has given consent to an evil temptation, ought to banish that anxiety altogether and to be sure that he has not consented. But suppose these evil temptations are importunate, and remain in the soul even when we resist them, and try to turn from them? No matter. They do not become sins on that account; nay, they become the occasion of acts of great virtue. {117} It is related in the life of St. Catherine of Sienna that on one occasion that pure virgin's soul was assailed by the most horrible temptations of the devil. They lasted for a long time, and after the conflict our Saviour appeared to her with a serene countenance.