The Gospels show us that Jesus loved His Jewish heritage and was observant of the Law. At the same time, we often see Him in conflict with the religious leaders who criticize His healings on the Sabbath or who question His apparent lack of attention to traditional cleansing rituals. They complain that He draws to Himself those who, in their opinion, should be disregarded as “sinners.” Did Jesus disregard the Mosaic Law?
In today’s Gospel, we hear Jesus saying, “You have heard the commandment imposed on your forefathers…but I say to you…” Was Jesus setting aside the Law of Moses?
The religious leaders of Jesus’ day were convinced that if you were not to break the Law, you had to avoid everything that might lead to breaking the Law. If you were to observe the Sabbath, you should know how far you could walk on the Sabbath or to what extent preparing food violated the Sabbath rest. For this purpose, secondary rules developed that were meant to act as a “hedge around the Law.”
According to the Gospels, Jesus resisted social pressure to regard secondary rules with the same importance as the commandments. St. Thomas Aquinas explains that Jesus refused “to abstain from doing even works of kindness on the Sabbath, which was contrary to the intention of the Law” (1a2ae. 107, 2, ad 3).
As we can see in today’s Gospel from the Sermon on the Mount, Jesus asserted that the Commandments must be kept. St. Thomas Aquinas affirms that Jesus fulfilled the Law “by explaining the true sense of the Law” (1a2ae. 107, 2). He went further than the Law itself because He insisted that the Commandments must be kept from the inside out, including our interior thoughts and dispositions(Commentary on the Gospel of St. Matthew).
It is not enough not to kill, we should not hate or grow angry. It is not enough not to commit adultery, we should not lust interiorly. Thomas explains:
The Law fixed a limit to revenge, by forbidding men to seek vengeance unreasonably: whereas Our Lord deprived them of vengeance more completely by commanding them to abstain from it altogether. With regard to hatred of one’s enemies, He dispelled the false interpretation… by admonishing us to hate, not the person, but his sin… (1a2ae. 107, 2).
Has Jesus made keeping the commandments more difficult? Thomas comments: “The precepts of the New Law are more burdensome than those of the Old; because the New Law prohibits certain interior movements of the soul, which were not expressly forbidden in the Old Law in all cases” (1a2ae. 107, 4).
Is it actually possible not to be angry or to hate or not to feel sexual attractions? Controlling our thoughts or feelings doesn’t come automatically. Thomas distinguishes between these feelings that are “a movement of the mind, which is either sudden or with deliberation” (Commentary on the Gospel of St. Matthew). We are less responsible for spontaneous thoughts or feelings but we are responsible if we nurture them with deliberation.
St. Thomas believes that we are able to give order to the spontaneous thoughts and feelings by developing good habits, which are the virtues. According to Thomas, virtue enables believers to act well: “to act thus is difficult for a man without virtue but through virtue it becomes easy for him” (1a2ae. 107, 4).
Some virtues are simply given by God. Many of the virtues, similar to other habits, are built up by repeating an action. Of course, we need God’s help in repeating these actions as well. When we build up the virtues, we act in a virtuous way, “promptly and with pleasure” (1a2ae. 107, 4).
One way of confirming the habit of virtuous actions is to take responsibility when we have acted otherwise. Thomas echoes Augustine’s advice that we prepare to approach God at the altar of the church or at the altar of our heart, “by prostrating yourself humbly in the presence of the One to whom you are about to offer; if he [the injured person] is present, he must be returned to your love by seeking pardon from him” (Commentary on the Gospel of St. Matthew).
Thomas recognizes that the person may not have offended us justly: “He does not add ‘justly’, He makes it plain that even the one who suffered the injury ought to seek friendship (Commentary on the Gospel of St. Matthew).
Thomas recalls the words of both the Old and New Testaments: "You shall not hate your brother in your heart" (Lv 19:17) and "Do not let the sun go down on your anger" (Eph. 4:26).
For Thomas, we need to be concerned about the effect that harboring negative feelings has on ourselves: “… not only because we harm the neighbor, but because we give the unclean spirits room within us for doing what they will” (Commentary on the Gospel of St. Matthew).
Thomas turns to the advice of St. John Chrysostom: “If you have offended by thought, be reconciled by thought; if by words, by words; if by deeds, by deeds” (Commentary on the Gospel of St. Matthew). At times, we need to apologize by words, at times by our actions but, at other times, we need to make peace in our thoughts when we have sinned against another by thought.
According to Thomas, the New Law, given by Jesus, is not a revised list of updated regulations but an inner principle that enables us to do good. Thomas states: “The New Law consists chiefly in the grace of the Holy Spirit, which is shown forth by faith that works in love” (1a2ae. 106, 1, 2; 108, 1).
Ultimately, we need to pray for a greater love because love enables us to act in a good way. Thomas frequently returns to Augustine’s explanation of 1 John 5:3: “His commandments are not heavy.” Augustine wrote: ”They are not heavy to the man who loves; whereas they are a burden to him who loves not.”
Denis Vincent Wiseman, O.P.
 References to the Summa Theologiae give the part of the Summa, which, in this case, is the first part of the second half (Prima Secundae), followed by the question, which is 107, and the article, which is 2, and, in this case, in response to the 2nd objection that he raised at the beginning of the article.