An intolerance, accompanied generally by some measure of emotional disturbance, of another's possession of a good that one wishes to belong exclusively to himself. It expresses itself often in suspicion, anger, hurt feelings, depression, etc., and sometimes issues in thoughts, words, or deeds contrary to justice and charity. In ordinary speech as well as in theological literature it is not always clearly distinguished from envy, although better usage favors taking envy to mean any coveting for oneself of a good possessed by another, and jealousy the desire for the exclusive possession of something.
St. Paul lists jealousy under the 15 works of the flesh (Gal 5.19–21) and under the 11 acts unworthy of a Christian (2 Cor 12.20–21). In these lists St. Paul piles up synonyms as is his custom, and his vocabulary is identical with that of the Stoics. Through St. Gregory the Great the capital sins of the Stoics were introduced into Christian terminology. Jealousy seems to be what St. Gregory meant by the fourth species of pride, whereby one is led to cherish the idea that he is the sole possessor of a given type of excellence. In the Summa Theologiae St. Thomas Aquinas seems to make jealousy synonymous with envy, in which form it appears as a capital sin, but it is doubtful that he had in mind jealousy used in the same sense as here defined.
The word jealousy is sometimes used without pejorative connotation, as in Ex 20.5: "For I, the Lord, your God, am a jealous God, …" The desire for the exclusive possession of something is not necessarily unreasonable, for one's right to such possession may be well founded, and its vindication is not sinful if it is accomplished in an ordinate manner. But when the claim to exclusive right is unjustified, or when its vindication involves violations of charity or justice, it is more or less gravely sinful, depending upon the harm that is done.
Exaggerated jealousy in the form of suspicion and resentment are symptoms often associated with such pathological states as melancholy, paranoia, and alcoholism. In such instances it can be assumed that what appears to be jealousy has no moral significance or that its moral quality is greatly attenuated. This is true also of the apparent jealousy found in the senile who suffer from cerebral arteriosclerosis.
Bibliography: f. roberti et al., Dictionary of Moral Theology, ed. p. palazzini et al., tr. h. j. yannone et al., from 2d Ital. ed. (Westminster, MD 1962). thomas aquinas, Summa Theologiae 1a2ae, 28.4; 2a2ae 36.4, 162.4.
"Jealousy." New Catholic Encyclopedia. . Encyclopedia.com. (August 15, 2018). http://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/jealousy
"Jealousy." New Catholic Encyclopedia. . Retrieved August 15, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/jealousy