Verse 17. - My house shall be called a house of prayer for all the nations (πᾶσι τοῖς ἔθνεσιν). St. Mark, writing for Gentiles, assures them that the God of the Jews is the God of all the nations; and that the court of the Gentiles, which was then so profaned, was a constituent part of his house of prayer. St. Jerome notes Christ's action in driving out the profaners of the temple as a great proof of his Divine power, that he alone should have been able to cast out so great a multitude. He says, "A fiery splendor flashed from his eyes, and the majesty of Deity shone in his countenance." The words, "My house shall be called the house of prayer," are a quotation from Isaiah 56:7; and it is a remarkable coincidence that in Ver. 11 of that chapter the rulers of the people are described as looking "every one for his gain from his quarter." A den of thieves (σπήλαιον ληστῶν); this should be rendered, a den of robbers. The Greek word for "thief" is κλέπτης, not ληστής. The two terms are carefully distinguished in St. John (John 10:1), "the same is a thief (κλέπτης) and a robber (λῃστής)." These priests, wholly intent upon gain, by various fraudulent acts plundered strangers and the poor, who came purchase offerings for the worship of God. Observe that the temple is called the house of God, not because he dwells in it in any corporeal sense, for "he dwelleth not in temples made with hands," but because the temple is the place set apart for the worship of God, in which he specially gives ear to the prayers of his people, and in which he specially promises his spiritual presence. Hence we learn what reverence is due to the houses of God; so that, as the master of a house resents any insult offered to his house as an insult to himself, so Christ reckons any wilful dishonor done to his house as a wrong and insult to him.

11:12-18 Christ looked to find some fruit, for the time of gathering figs, though it was near, was not yet come; but he found none. He made this fig-tree an example, not to the trees, but to the men of that generation. It was a figure of the doom upon the Jewish church, to which he came seeking fruit, but found none. Christ went to the temple, and began to reform the abuses in its courts, to show that when the Redeemer came to Zion, it was to turn away ungodliness from Jacob. The scribes and the chief priests sought, not how they might make their peace with him, but how they might destroy him. A desperate attempt, which they could not but fear was fighting against God.And he taught, saying unto them, is it not written,.... In Isaiah 56:7.

My house shall be called of all nations, the house of prayer? For not only the Jews went up to the temple to pray, see Luke 18:10, but the Gentiles also, who became of the Jewish religion, and had a court built for that purpose; and so the whole temple, from hence, was called an house of prayer: and the meaning is, not only that it should be called so by the Gentiles, but that it should be so to them, and made use of by them as such. Jarchi's note on the clause in Isaiah 56:7 is, "not for Israel only, but also for the proselytes."

But ye have made it a den of thieves; for no other, in our Lord's esteem, were the buyers and sellers of sheep, oxen, and doves, and the money changers, and the priests that encouraged them, and had a profit out of them: now these had their seats, shops, and tables, within the mountain of the house; and even in that part of it, which was assigned to the Gentiles, the nations of the world, who became proselytes, and came up to Jerusalem to worship there at certain times; See Gill on Matthew 21:13.