Before this proposition is demonstrated, we will first explain the derivation and nature of charity, of faith, and of good works which are called fruits. Faith is truth; wherefore the doctrine of faith is the doctrine of truth, and the doctrine of truth is in the understanding, thence in the thought, thence in the speech. Wherefore, it teaches what should be willed and what should be done; thus, that evils are to be shunned, and which evils in particular; and that good actions are to be done, and which in particular. When man does good from faith, goods unite themselves with truths, because the will is then united with the understanding; for good belongs to the will and truth to the understanding. From this conjunction arises the affection of good, which in its essence is charity, and the affection of truth, which in its essence is faith; and these two united make a marriage. From this marriage good works are produced as fruits from a tree; whence they become the fruits of good and the fruits of truth. The latter are signified in the Word by grapes, the former by olives.