We should inquire as to the kind of fruit the Lord wishes us to recognize, so that we may be able to distinguish the tree. Many persons reckon as fruits certain things which are indeed the suitable clothing of sheep, for instance, fastings, prayers, and almsgivings. Such people are deceived by wolves, for, if these things could not be done also by hypocrites, the Lord would not have previously said: “Take heed not to practice your righteousness before men, in order to be seen by them” (Mt 6,1)… Many persons bestow much upon the poor, not through mercy, but for the sake of display; many persons pray-or, rather, they seem to pray-without directing their attention toward God, but seeking to please men; and many persons fast and display a wonderful degree of self-denial before those who think such things difficult and praiseworthy… These are not the fruits by which a tree can be recognized in accordance with the Lord’s admonition. When these things are truly done with a good intention, they are rightly called the clothing of sheep… The Apostle Paul tells us what are the known fruits by which we may recognize a bad tree. He says: “Now the works of the flesh are manifest: they are immorality, uncleanness, licentiousness, idolatry, witchcraft, enmity, contention, jealousy, animosity, quarrels, heresies, faction, envy, drunkenness, carousings, and such like things” (Gal 5,19-21)… And the same Apostle goes on to tell us also what are the fruits by which we may recognize a good tree, for he says: “But the fruit of the spirit is: charity, joy, peace, patience, kindness, goodness, faith, modesty, continence” (vv. 22-23). So, also, the word ‘joy’ is likewise used in its proper sense here, for evil men are not said to rejoice, but to enjoy pleasure… It is in this proper sense that the good use the word when they say: “Rejoicing is not for the wicked, says the Lord” (Is 57,21 cf. Vg.)… The same applies to the true faith. In wicked and deceitful men there are also certain semblances of the other virtues… that may thoroughly deceive anyone who does not keep clear and single the eye through which one is able to recognize those virtues.
Roman Extraordinary (Tridentine) Daily Readings – rosary,team