20 For I tell you, that unless your justice abound more than that of the scribes and Pharisees, you shall not enter into the kingdom of heaven.
Chrysostom: By righteousness is here meant universal virtue. But observe the superior power of grace, in that He requires of His disciples who were yet uninstructed to be better than those who were masters unto the Old Testament. Thus He does not call the Scribes and Pharisees unrighteous, but speaks of “their righteousness.” And see how ever herein He confirms the Old Testament that He compares it with the New, for the greater and the less are always of the same kind.
Pseudo-Chrysostom: The righteousness of the Scribes and Pharisees are the commandments of Moses; but the commandments of Christ are the fulfilment of that Law. This then is His meaning; Whosoever in addition to the commandments of the Law shall not fulfil My commandments, shall not enter into the kingdom of heaven.
21 You have heard that it was said to them of old: Thou shalt not kill. And whosoever shall kill shall be in danger of the judgment. 22 But I say to you, that whosoever is angry with his brother, shall be in danger of the judgment.
Augustine: Because they knew not of any murder, besides the destruction of the body, the Lord shews them that every evil thought to the hurt of a brother is to be held for a kind of murder.
We do not, because we have heard that, “Thou shalt not kill,” deem it therefore unlawful to pluck a twig, according to the error of the Manichees, nor consider it to extend to irrational brutes; by the most righteous ordinance of the Creator [Gen 1:29-30] their life and death is subservient to our needs.
Yet have not they in any way done contrary to this commandment who have waged wars under God’s authority, or they who charged with the administration of civil power have by most just and reasonable orders inflicted death upon criminals.
He is not angry with a brother who is angry at his offence. He then it is who is angry without cause, who is angry with his brother, and not with the offence.
To be angry with a brother to the end that he may be corrected, there is no man of sound mind who forbids. Such sort of motions as come of love of good and of holy charity, are not to be called vices when they follow right reason.
Pseudo-Chrysostom: He who is angry without cause shall be judged; but he who is angry with cause shall not be judged. For if there were no anger, neither teaching would profit, nor judgments hold, nor crimes be controlled. So that he who on just cause is not angry, is in sin; for an unreasonable patience sows vices, breeds carelessness, and invites the good as well as the bad to do evil.
He whose anger arises from just cause does not suffer any passion, and is rightly said to sentence, not to be angry with.
Scripture from the Douay-Rheims Bible. Commentary from St. Thomas Aquinas, Catena Aurea, Vol. I (London: Rivington, 1842).