Mt 21:12-13, Mk 11:15-17, Lk 19:45-46, Acts 13:46-48
In the Old Testament, God said that the temple of God would be called the house of prayer for all people. (Isa 56:7)
Isa 56:7 Even them will I bring to my holy mountain, and make them joyful in my house of prayer: their burnt offerings and their sacrifices shall be accepted upon mine altar; for mine house shall be called an house of prayer for all people.
Jesus quoted the Old Testament as saying that the temple of God is a house of prayer and drove out those who traded in front of the temple. (Matthew 21:12-13, Mark 11:15-17, Luke 19:45-46)
Matthew 21:12 And Jesus went into the temple of God, and cast out all them that sold and bought in the temple, and overthrew the tables of the moneychangers, and the seats of them that sold doves, 13 And said unto them, It is written, My house shall be called the house of prayer; but ye have made it a den of thieves.
Mark 11:15 And they come to Jerusalem: and Jesus went into the temple, and began to cast out them that sold and bought in the temple, and overthrew the tables of the moneychangers, and the seats of them that sold doves; 16 And would not suffer that any man should carry any vessel through the temple. 17 And he taught, saying unto them, Is it not written, My house shall be called of all nations the house of prayer? but ye have made it a den of thieves.
Luke 19:45 And he went into the temple, and began to cast out them that sold therein, and them that bought; 46 Saying unto them, It is written, My house is the house of prayer: but ye have made it a den of thieves.
This gospel was directed to the Gentiles because the Jews did not receive God's word that Jesus was the Christ. (Acts 13:46-48)
Acts 13:46 Then Paul and Barnabas waxed bold, and said, It was necessary that the word of God should first have been spoken to you: but seeing ye put it from you, and judge yourselves unworthy of everlasting life, lo, we turn to the Gentiles. 47 For so hath the Lord commanded us, saying, I have set thee to be a light of the Gentiles, that thou shouldest be for salvation unto the ends of the earth. 48 And when the Gentiles heard this, they were glad, and glorified the word of the Lord: and as many as were ordained to eternal life believed.