377. (3) Good works are not produced by charity alone, still less by faith alone, but by charity and faith together. This is because charity apart from faith is not charity, and faith apart from charity is not faith (as shown above, n. 356-361). Wherefore charity cannot exist by itself or faith by itself; and it cannot be said that charity in itself produces any good works, or faith in itself. It is the same with these as with the will and understanding. The will by itself can have no existence and can therefore produce nothing; nor can the understanding have any existence by itself of produce anything; but all production is effected by both together, and is effected by the understanding from the will. There is this similarity, because the will is the abode of charity and the understanding is the abode of faith. It is said that still less can faith alone produce good works, because faith is truth, and faith operates to produce truths, and these illuminate charity and its exercises. That truths illuminate, the Lord teaches, saying:
He that doeth truth cometh to the light, that his works may be made manifest that they have been wrought in God (John 3:21).
Consequently when man does good works in accordance with truths, he does them in light, that is, intelligently and wisely. The conjunction of charity and faith is like the marriage of husband and wife. From the husband as a father and the wife as a mother all natural offspring are born; and in like manner from charity as a father and faith as a mother all spiritual off spring, which are knowledges of good and truth, are born. This makes clear how spiritual families are generated. Moreover in the Word "husband" and "father" signify in the spiritual sense the good of charity, and "wife" and "mother" the truth of faith. This again makes clear that neither charity alone nor faith alone can produce good works, as neither the husband alone nor the wife alone can produce offspring. The truths of faith not only illuminate charity, but also determine its quality, and, still further, nourish it; so that a man having charity but no truths of faith, is like one walking in a garden, at night, who plucks fruit from the trees, not knowing whether in its use it is good or bad fruit. As the truths of faith not only illuminate charity but also determine its quality, as before said, it follows that charity without the truths of faith is like fruit without juice, like a dried-up fig, or like a grape after the wine has been pressed out of it. As truths nourish faith, as has also been said, it follows that if charity is without truths of faith, it receives no nourishment except such as a man gets from eating burnt bread and drinking unclean water from some stagnant pond.