18 If the Pagan, in the next place, were to find fault with both Testaments as attributing jealousy to God and Christ, he would only show his own ignorance of literature, or his forgetfulness. For though their philosophers distinguish between desire and passion, joy and gratification, caution and fear, gentleness and tender-heartedness, prudence and cunning, boldness and daring, and so on, giving the first name in each pair to what is good, and the second to what is bad, their books are notwithstanding full of instances in which, by the abuse of these words, virtues are called by the names which properly belong to vices; as passion is used for desire, gratification for joy, fear for caution, tender-heartedness for gentleness, cunning for prudence, daring for boldness.
The cases are innumerable in which speech exhibits similar inaccuracies. Moreover, each language has its own idioms. For in religious writings I remember no instance of the word tender-heartedness being used in a bad sense. And common usage affords examples of similar peculiarities in the use of words. In Greek, one word stands for two distinct things, labor and pain; while we have a separate name for each. Again, we use the word in two senses, as when we say of what is not dead, that it has life; and again, of any one that he is a man of good life, whereas in Greek each of these meanings has a word of its own.
So that, apart from the abuse of words which prevails in all languages, it may be an Hebrew idiom to use jealousy in two senses, as a man is called jealous when he suffers from a diseased state of mind caused by distress on account of the faithlessness of his wife, in which sense the word cannot be applied to God; or as when diligence is manifested in guarding conjugal chastity, in which sense it is profitable for us not only unhesitatingly to admit, but thankfully to assert, that God is jealous of His people when He calls them His wife, and warns them against committing adultery with a multitude of false gods.
The same may be said of the anger of God. For God does not suffer perturbation when He visits men in anger; but either by an abuse of the word, or by a peculiarity of idiom, anger is used in the sense of punishment.
Source: Reply to Faustus the Manichaean (New Advent)