Joshua 19:50

In what precedes it was indeed said that "the sons of Israel gave a portion by lot to Jesus on Mount Ephraim," and that, the lot having been received, "Jesus built a city there and dwelt in it." But now Scripture repeats the same thing anew, so as to add this: that "he stored away in that city, which he had built and in which he was dwelling, the flint knives," that is, the blades of stone, "with which Jesus circumcised the sons of Israel in the wilderness." Hence for us too the exposition must be repeated, and this too, which has been added, must be explained, so that, by God's gift, the meaning of Scripture may be fulfilled entire. For we said in what precedes that our Lord Jesus Christ also seeks from us a place which he may build and in which he may dwell, and that we ought to become such — so "clean of heart," so "simple in mind," so "holy in body and spirit" — that he may deign both to receive a place in our soul, and to build it, and to dwell in it. And who, do you suppose, are in all the people so acceptable to God as to be worthy to be chosen for this? Or perhaps not even individuals can be capable of this, but the whole people and the entire church together can scarcely be capable of it, of receiving the Lord Jesus into itself and having him dwell in it? Let us see, then, what this place is in which Jesus ought to dwell. "On the mount," he says, "of Ephraim," that is, on the fruitful mount. Who, do you suppose, are in us the fruitful mounts on which Jesus may dwell? Assuredly those in whom are "the fruits of the spirit, joy, peace, patience, charity," and the rest. These, then, are the fruitful mounts, which bring forth "the fruit of the spirit" and are always lofty in mind and in hope. And though such may be few, nevertheless, if there be even a few, the Lord Jesus dwelling in them, who is "the true light," will send forth the rays of his light even upon all the rest, whom he has not yet judged worthy of his dwelling in the first place.

Now, then, let us see what are "the flint knives, with which Jesus circumcised the sons of Israel." If you pray for us, that "our word may be living and effective and sharper than any knife," the Lord Jesus will grant us also that the word of God which we speak to you may circumcise every uncleanness, cut back the impurities, sever the vices from the hearers, and amputate everything by which the force of the mind and its natural effectiveness is overlaid; and thus, through the word of God, which is now called "the flint knife," you too will be circumcised by Jesus, and you will hear that: "today I have taken away from you the reproach of Egypt." For what does it profit us to have gone out of Egypt and to carry about with us "the reproaches of Egypt"? What does it profit to walk through the wilderness — that is, what does it help us to have renounced the world in baptism and to retain the former filth of our habits and the uncleannesses of the carnal vices? It is necessary, therefore, after the passage of the Red Sea — that is, after the grace of baptism — that the carnal vices of our old habit also be taken away from us through our Lord Jesus, so that thus at last we may be able to lack "the reproaches of Egypt." Those very "flint knives," then, and stone blades, with which we were a second time circumcised by Jesus, are placed in that place which Jesus seeks and has received; in the place which he possesses in the soul of the just man, in that very place he also stores away the "knives." We have often shown that the "knife" is said to be the word of God, by which word sins are cut away and purged from the souls of the hearers. This power of the divine word, therefore, is stored away in that place to which is given the word of knowledge and the word of wisdom, so that at an opportune time that soul, which through the gift of the spirit has been filled with the word of wisdom and the word of knowledge, may bring forth these "knives" in the church and may circumcise a second time those who have need of a "second circumcision." But as for his saying "flint knives," that is, blades of stone and not blades fashioned of iron by the workman's craft, this shows that this word of God, which can circumcise the uncleannesses from the hearts of the hearers, does not come from the art of grammar or rhetoric, nor has been tamed by the hammers of the learned or filed down…