If you read the stories told in Matthew 21, Mark 11, and Luke 19, you will see Jesus clearing the temple. The action we can visualize, but what was it he said and what does it mean?
Jesus takes two already used prophetic words from Isaiah 56:7 and Jeremiah 7:11 and combines them into a powerful statement. 1) My house is to be a house of prayer for all people. 2) You have made it a den of robbers.
The context of Isaiah is salvation for eunuchs and foreigners, the desire of God for all people to seek His face, for his house (whether metaphorical or literal temple or heaven) is a house of prayer for all nations, not just Israel. Israel had a tendency, like we do, to prefer a certain class of people, shut out and distrust others, think them less likely to be included in the scope of God's grace.
Yahweh dispels such notions by saying that the foreigners, the eunuchs who worship Yahweh, keep His covenant commands will be brought to His holy mountain, into his holy house that is to be a house of prayer for all nations.
Jesus was bringing together this idea with the prophet Jeremiah's criticism of the people leaning so hard on their tie to the physical temple instead of Yahweh, to their corrupt practices and showy ways that attempted to cover up their deceit.
PRAYER, FASTING, GIVING
Will our places of worship be houses of prayer for all people? Or just people like us? In what ways can we make our places of worship, our churches a den of robbers? Is there something we need to confess that we are not obedient to in these prophetic words Jesus speaks? What kind of releasing of our assets (money, time, energies) do we need to be obedient to this prophetic word?