What is pulled down must also be destroyed
There is a building of the devil, and there is a building of God. The building 'on the sand' is the devil's, for it stands on nothing firm and sure and united. The building 'on the rock' is God's. See what is said to those of God: 'You are God's field, God's building.' So the words of God are over 'nations and kingdoms, to uproot and to pull down and to destroy.' If something is uprooted, and what was uprooted is not destroyed, it is still there. If something is pulled down, and the stones of the demolition are not destroyed, it is still there.
It is a work of the goodness of God, after the uprooting, to destroy what has been uprooted, and after the taking-down, to destroy what has been taken down. Read carefully how such things are destroyed: 'Burn the chaff with unquenchable fire,' and 'Bind the tares in bundles and hand them over to fire.' So after being uprooted they are destroyed. And if you want to see also the things destroyed after demolition, of the building of poor stuff: that house which was taken down because of leprosy becomes dust, and being dust it is thrown 'outside the city,' so that not even a stone remains, like 'I will grind them as the mud of the streets.' For the worse things must in no way still stand. Something has been pulled down: let the stones not be useful for another building which the evil one can build. Something has been uprooted: let him not again find seeds from the uprooted things, so as to sow the tares once more. For having the seeds of the tares he certainly sowed them. That is why 'bind the tares and burn them with fire,' so that after being uprooted they may be destroyed, and after being pulled down the devil's building may be destroyed.
Greek
ἔστι τις οἰκοδομὴ τοῦ διαβόλου, ἔστι τις οἰκοδομὴ τοῦ θεοῦ. ἡ «ἐπὶ τὴν ἄμμον« οἰκοδομὴ τοῦ διαβόλου ἐστίν, ἐπ᾿ οὐδενὶ γὰρ ἐστήρικται ἑδραίῳ καὶ βεβαίῳ καὶ ἡνωμένῳ· ἡ δὲ οἰκοδομὴ ἡ «ἐπὶ τὴν πέτραν« τοῦ θεοῦ ἐστιν. ὅρα τί λέγεται τοῖς τοῦ θεοῦ· «θεοῦ γεώργιον, θεοῦ οἰκοδομή ἐστε. οἱ λόγοι τοίνυν τοῦ θεοῦ «ἐπὶ ἔθνη καὶ βασιλείας« εἰσίν, «ἐκριζοῦν καὶ κατασκάπτειν καὶ ἀπολλύειν. ἐὰν ἐκριζωθῇ μέν, μὴ ἀπόληται δὲ τὸ ἐκριζωθέν, ἔστι τὸ ἐκριζωθέν. ἐὰν κατασκαφῇ μέν, οἱ λίθοι δὲ τῆς κατασκαφῆς μὴ ἀπόλωνται, ἔστι τὸ κατασκαφέν.
ἔργον οὐν ἐστι τῆς ἀγαθότητος τοῦ θεοῦ, μετὰ τὸ ἐκριζῶσαι ἀπολέομαι τὸ ἐξερριζωμένον, μετὰ τὸ καθελεῖν ἀπολέσαι τὸ καθῃρημένον. ἀνάγνωθι ἐπιμελῶς ἐπὶ μὲν τῶν ἀπολλυμένων καὶ ἐκριζουμένων, πῶς ἀπόλλυνται τὰ τοιαῦτα· >τὸ δὲ ἄχυρον κατακαύσατε πυρὶ ἁσβέστῳ< καί δήσατε δέσμας ζιζάνια καὶ παράδοτε αὐτὰ πυρί< οὕτως μετὰ τὸ ἐκριζοῦσθαι ἀπόλλυται. εἰ θέλεις ἰδεῖν καὶ μετὰ καθαίρεσιν τὰ ἀπολλύμενα τῆς οἰκοδομῆς τῆς ὕλης τῆς φαύλης· χοῦς γίνεται ἡ οἰκία ἐκείνη ἡ διὰ τὴν λέπραν καθῃρη- μένη καὶ ἐκβάλλεται χοῦς γενομένη «ἔξω τῆς πόλεως«, ἵνα μηδὲ λίθος ᾖ μένων, ὁμοίως τῷ «ὡς πηλὸν πλατειῶν λεανῶ αύτούς«· δεῖ γὰρ μηδαμῶς συνεστάναι τὰ χείρονα. κατεσκάφη τι, μὴ οἱ λίθοι ἔστωσαν χρήσιμοι πρὸς [τὴν] ἄλλην οἰκοδομήν, ἣν δύναται οἰκοδομεῖν ὁ πονηρός· ἐξερριζώθη, μὴ πόλιν ἐκ τῶν ἐξερριζωμένων εὕρῃ σπέρματα, ἕνα ἐπισπείρῃ πάλιν τὰ ζιζάνια, πάντως γὰρ ἔχων τὰ σπέρματα τῶν ζιζανίων, ἐπέσπειρεν αὐτά. διὰ τοῦτο δήσατε τὰ ζιζάνια καὶ κατακαώσατε αὐτὰ πυρί< ἵνα μετὰ τὸ ἐκριζωθῆναι ἀπόληται, καὶ μετὰ τὸ κατασκαφῆναι ἡ τοῦ διαβόλου οἱκοδομὴ ἀπόληται.