The Meaning of Mercy

To mark the Feast of St. Thomas Aquinas (1225-1274) on Jan. 28, the following is the first of a two-part series on the saint who explained in the greatest depth why Divine Mercy is central to the faith of the Church. This series is extracted from the book by Robert Stackpole, STD, Divine Mercy: A Guide from Genesis to Benedict XVI (Marian Press):

Aquinas defined the virtue of "mercy" in his Summa Theologiae as "the compassion in our hearts for another person's misery, a compassion which drives us to do what we can to help him" (ST II-II.30.1). For St. Thomas, this virtue has two aspects: "affective" mercy and "effective" mercy.

Affective mercy is an emotion: the pity we feel for the plight of another. In this respect, St. Thomas says, human mercy is grounded in a "defect" in our nature: the defect of human vulnerability to suffering. We feel pity for those who suffer because we, too, are subject to such miseries. Thus, our affective sympathy for others arises from our capacity for empathy. Saint Thomas notes: "Those who reckon themselves happy and so powerful that no ill may befall them are not so compassionate" (II-II.30.2). To some extent, however, the intensity of our affective mercy for the plight of another also depends upon how closely we are united to others in friendship: "The person who loves regards his friend as another self, and so he counts his friend's troubles as his own, and grieves over them as if they were his own" (II-II.30.2). An affective bond, we might say, easily forms between friends, and this renders good friends all the more capable of sympathy for each other's plight. For example, when we hear that a friend or a loved one is about to go through a major surgery, we naturally feel compassion for them, and we say to ourselves, "I can imagine what anxiety my friend is going through right now on the eve of his operation." We can "imagine" it because we have been sick and in need of medical treatment ourselves. This sympathetic empathy is what St. Thomas means by "affective mercy."

Effective mercy, on the other hand, is something that we do, a positive action for the good of another, taking steps to relieve the miseries or meet the needs of others. According to St. Thomas, the Latin word misericordia literally means "having a miserable heart" - both affectively and effectively - for another person's misery. For example, when we hear that our friend is on the eve of major surgery, we not only feel sympathetic empathy for him, we also may plan to go and visit him in the hospital before and after the operation to comfort him. This is "effective" mercy because it actively meets the needs of others. In other words, it is "affective" sympathy translated into "effective" action for the good of another.

Saint Thomas observes that there are three kinds of "misery" in this life. First, there is the suffering that goes against our natural appetite for existence and life, such as the misery of a sick man. Secondly, there is suffering that strikes us suddenly and unexpectedly, such as sufferings arising from accidents. The third kind of suffering, however, is the worst of all: suffering that strikes a person when he consistently pursues the good, yet he meets only overpowering evil. Saint Thomas here has in mind those sufferings and misfortunes that strike those who in no way deserve them, the undeserved miseries of the innocent and the virtuous. In the Old Testament, Job is an example of this form of misery. He was overwhelmed with undeserved grief and sorrows of every kind.

Saint Thomas argues that the human virtue of mercy necessarily will be both affective and effective. However, to be the authentic virtue of mercy, it must manifest two additional characteristics. First, it must be rooted in "right reason" - that is, in the truth about the sufferings of others, and what is in fact the objective "good" for the other whom we seek to help. For example, a drunkard may suffer severe shaking and trembling from a day without alcohol, but "right reason" suggests that the best remedy for his problem is not to give him a glass of liquor, even though that may temporarily relieve his symptoms - and even though he may beg for one! The merciful thing to do is to provide for the drunkard what he truly, objectively needs: a few days in a detoxification center. Second, the virtue of mercy is proven in effective action for the good of others, as circumstances permit. If we merely "sympathize" with the plight of others and "share their pain" without making the best of the opportunities we have to help them, then the virtue of mercy does not abide in us to any significant degree.

Saint Thomas asks two related questions. First, is mercy the greatest of the human virtues? It certainly implies a measure of grandeur and nobility, insofar as effective mercy is the generous relief of the needs and miseries of others out of one's own abundance. We help others out of our store of wealth, knowledge, skill, or strength when we see others in need of such help. In that sense, mercy is an act of condescension from one person who has a greater abundance of some good to another person lacking in some good. If the merciful person has a superior (that is, someone with an even greater abundance of goods to share) then his chief virtue will be what unites him with his superior. In the case of human beings, the virtue of "charity" is what unites us to God (since God is not in need of our mercy): "Since man, therefore, has God above him, charity which unites him to God is greater than mercy, which relieves the wants of others" (II-II.30.4). On the other hand, when we consider which of the virtues should govern our relationships with other human beings, then it is clear that mercy directed to our neighbors in need is the supreme virtue in man (II-II.30.4).

Second, St. Thomas asks: Is mercy the greatest attribute of God? Since God is the absolute superior, the perfect and self-existent creator, St. Thomas says, He is never self-seeking, but acts only and always with selfless generosity, pouring good gifts out of His abundance on His creatures. Showing mercy is therefore proper to God in a special way, for it manifests His infinite perfection, and His infinite abundance and generosity. Saint Thomas writes: "If we consider a virtue in terms of its possessor, however, we can say that mercy is the greatest of the virtues only if its possessor is himself the greatest of all beings, with no one above him and everyone beneath him" (II-II.30.4). This, of course, is properly true only of God Himself. Thus, mercy is, in that sense, the greatest attribute of God.

What, then, is the mercy of God, according to St. Thomas? It cannot be an emotion or a passion since God in His infinite, immutable perfection cannot be subject to changing passions that "happen" to Him, "overcome" Him, or reduce His fullness of Being in any way. Thus, St. Thomas argues that God's mercy is "effective," not "affective." In other words, His mercy is expressed in the positive action that His love takes to remedy the miseries and meet the needs of His creatures, communicating to them a share in His own perfections. Aquinas writes: "To feel sad about another's misery is no attribute of God, but to drive it out is supremely His, and by misery here we mean any sort of defect. Defects are not done away with save by an achievement of goodness, and as we have said, God is the first source of goodness" (I.21.3).

According to St. Thomas, it is above all the forgiveness of sins that manifests God's mercy. The forgiveness of our sins is an act of God's omnipotence: God's love showing itself to be more powerful than sin and evil. When human beings forgive one another, we control our anger, curb our resentment, and annul any claims of revenge. But we cannot remit the fault itself. God alone can change the will of the malefactor and turn his heart toward repentance. In this sense, God alone can remit sins. Thus, God's mercy is infinitely powerful to destroy sin and regenerate and sanctify the sinner.

For example, we see the powers of God's mercy at work in the New Testament when Jesus not only forgives the sins of the paralytic who was brought to Him, but shows His divine authority to do so by healing the man's body: "That you may know that the Son of Man has authority on earth to forgive sins ... I say to you, rise, take up your pallet and go home" (Mk 2:11).

In fact, St. Thomas claims, "Forgiving men, taking pity on them, is a greater work than the creation of the world" (I-II.113.9). As regards the mode of action, bringing the world into being out of nothing is the greater work, but in terms of the greatness of the work done, the justification of the unrighteous is the greater work, because it has an eternal effect. The justified and sanctified soul lives forever in God's kingdom, whereas this created world, as we now know it at least, passes away.

Read part two.

Robert Stackpole, STD, is director of the John Paul II Institute of Divine Mercy, an apostolate of the Marian Fathers of the Immaculate Conception. His latest book is Divine Mercy: A Guide from Genesis to Benedict XVI (Marian Press). Got a question? E-mail him at

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