Luke 14:29

(ubi sup.) For when occupied in good works, unless we watch carefully against the evil spirits, we find those our mockers who are persuading us to evil. But another comparison is added proceeding from the less to the greater, in order that from the least things the greatest may be estimated. For it follows, Or what king, going to make war against another king, sitteth not down first, and consultelh whether he be able with ten thousand to meet him that cometh against him with twenty thousand?

And behold, by these things He Who called thee to be His disciple hath taught thee that thou shouldst not begin in this path unless thou art determined to finish in it, and that thou shouldst not lay the foundations to build a tower, if thou hast it not in thy mind to finish it, and that thou shouldst not go forth to war against Satan, unless the hosts of mighty thoughts be gathered together about thee, lest having gone forth to war the Enemy overcome thee, and thy discipleship be blasphemed.

But we must consider what is said: "All who see it begin to mock him," because, according to the voice of Paul, "We have been made a spectacle to the world, to angels and to men." And in everything we do, we ought to consider our hidden adversaries, who always press upon our works, who always rejoice at our failure. Beholding these, the Prophet says: "My God, in you I trust; I shall not be ashamed, nor let my enemies mock me." For when we are intent upon good works, unless we vigilantly watch against malign spirits, we suffer as mockers the very ones we have as persuaders to evil.