And if this gold is impure in the end, it is because it has contracted fresh defilement by coming in contact with other bodies. But this impurity is only superficial, and does not prevent its being used; whereas its former impurity was hidden within it, and, as it were, identified with its nature. In addition to this, you will remark that gold of an inferior degree of purity cannot mix with that of a superior purity. The one must contract the impurity of the other, or else impart its own purity to it. Put a refined gold with an unrefined one, what can the goldsmith ever do with it? He will have all the impurity taken from the second piece, that it may be able to mix with the first. This is what St Paul tells us, that "the fire shall try every man's work of what sort it is;" he adds, that if any man's work should be found to deserve burning, he should be saved "so as by fire" (1 Cor. iii. 13, 15). That means, that though there are some works which are good, and which God receives, yet, so that he who has done them may be pure, they too must pass through the fire, in order that all appropriation, that is, all that was his own, may be taken from them. God will judge our righteousness, because "by the deeds of the law there shall no flesh be justified," but by "the righteousness of God, which is by faith" (Rom. iii. 20, 22). This being understood, I say that, in order that man may be united to his God, wisdom and divine justice, like a pitiless and devouring fire, must take from him all appropriation, all that is terrestrial, carnal, and of his own activity; and having taken all this from him, they must unite him to God. This is never brought about by the labours of the creature; on the contrary, it even causes him regret, because, as I have said, man so loves what is his own, and is so fearful of its destruction, that if God did not accomplish it Himself, and by His own authority, man would never consent to it.