Mark 11:17

So, then, brethren, if we do the will of our Father God, we shall be members of the first church, the spiritual, — that which was created before sun and moon; but if we shall not do the will of the Lord, we shall come under the Scripture which says, "My house became a den of robbers." [Jeremiah 7:11]

She has none to whom to make such a promise; and if she have had, she does not make it; since even the earthly temple of God can sooner have been called by the Lord a "den of robbers," than of adulterers and fornicators.

About this temple it is soon added: "My house is a house of prayer, but you have made it a den of thieves." For those who sat in the temple to receive gifts, it was certainly not doubtful that they would seek to harm those who gave nothing. Therefore the house of prayer had been made a den of thieves, because they knew how to stand in the temple for this purpose: either to eagerly pursue bodily those not giving gifts, or to kill spiritually those who did give.

To them it is rightly said: "My house is a house of prayer, but you have made it a den of thieves," because when perverse men sometimes hold a place of religion, there they slay with the swords of their malice where they ought to have given life to their neighbors through the intercession of their prayer.

The temple and house of God is also the very mind and conscience of the faithful. If at any time it brings forth perverse thoughts in injury to a neighbor, it is as though robbers are dwelling in a cave and killing those who walk by in simplicity, when they thrust swords of injury into those who are guilty of nothing. For the mind of the faithful is no longer a house of prayer but a den of thieves when, having abandoned the innocence and simplicity of holiness, it strives to do that by which it might harm its neighbors.

And He taught, saying to them: Is it not written that my house shall be called a house of prayer for all nations? He says, for all nations, not for one Jewish nation, nor in one place in the city of Jerusalem, but in the whole world, and not with the sacrifices of bulls and goats and rams, but with prayer.

But you have made it a den of robbers. Those who sat in the temple to receive gifts, certainly it was no doubt that they would seek harms from some who did not give. Therefore, the house of prayer had become a den of robbers, because they had learned to stand in the temple for this purpose, to either pursue those not giving gifts physically or to kill those giving spiritually. The temple and the house of God are also the mind and conscience of the faithful, which, if ever it produces perverse thoughts in the injury of a neighbor, resides as it were in a den of robbers. And they simply kill those walking uprightly, when they thrust swords into those who are guilty of no offense. For the mind of the faithful is no longer a house of prayer, but a den of robbers, when, having abandoned the innocence and simplicity of holiness, it strives to do that by which it may harm its neighbors.

It goes on: And he taught, saying unto them, My house shall be called of all nations the house of prayer. (Isa. 56:7)

(ubi sup.) He says, to all nations, not to the Jewish nation alone, nor in the city of Jerusalem alone, but over the whole world; and he does not say a house of bulls, goats, and rams, but of prayer.

(ubi sup.) For they were in the temple for this purpose, either that they might persecute with corporal pains those who did not bring gifts, or spiritually kill those who did. The mind and conscience of the faithful is also the temple and the house of God, but if it puts forth perverse thoughts, to the hurt of any one, it may be said that thieves haunt it as a den; therefore the mind of the faithful becomes the den of a thief, when leaving the simplicity of holiness, it plans that which may hurt others.

He calls moneychangers, changers of a particular sort of money, for the word means a small brass coin. There follows, and the seats of them that sold doves.

But if a man by sinning gives up to the devil the grace and purity of baptism, he has sold his Dove, and for this reason is cast out of the temple. There follows, And would not suffer that any man should carry any vessel through the temple.

Further, He calls the temple, a den of thieves, on account of the money gained there; for thieves always troop together for gain. Since then they sold those animals which were offered in sacrifice for the sake of gain, He called them thieves.

Which also turns to the greater condemnation of the Jews, because though the Lord did this so many times, nevertheless they did not correct their conduct.

John also narrates the expulsion of the money changers by Jesus, but he speaks of this at the beginning of the Gospel, whereas this one (Mark) speaks of it toward the end. Therefore one must think that this (latter) expulsion was the second, which serves to the greater condemnation of the Jews, since they did not repent despite the Lord having acted thus with them on more than one occasion. He calls the Temple a "den of robbers" on account of the covetousness of the money changers. For the robber race is given over to plundering. And since the sellers in the Temple also traded in sacrificial animals for the sake of gain, they too were called robbers. The "money changers" were engaged in the exchange of money. The Lord presents the prophet Isaiah as well as their accuser, who says: "My house shall be called a house of prayer" (Is. 56:7). Let us therefore pray that we too may not be cast out of the church! For many come to our church as well in order to sell what is good and buy what is bad. There are also those who, arranging and managing church affairs, have tables full of money: they do everything out of greed. Overturned also are the seats of those who sell doves, that is, the thrones of hierarchs who sell spiritual gifts, for the dove is an image of the Holy Spirit. May the Lord cast out such a bishop from his bishopric, for cursed is he who ordains for money. In like manner, he also sells his dove who sells to the devil the grace and purity received in baptism. For this reason he too is cast out of the Church.

According to Isaiah: But ye have made it a den of thieves, (Jer. 7:11) according to Jeremiah.