It is highly important that we read verse 11 as setting the scene. This tells us that Jesus went into the Temple and looked around it before going to spend the night with his dear friends in Bethany- Lazarus, Martha and Mary- as the village was less than two miles outside the city The next day, Jesus and the disciples returned to the Temple. It was then that He began to overturn the tables of the money-changers and those who sold doves. This was not an act due to lost temper, but a carefully-weighed up prophetic statement.
Each Jewish family had to bring an offering to God at Passover. There were different requirements for rich and poor: we know that Mary and Joseph, at the time of Jesus' birth, were not wealthy as they sacrificed two turtle doves in thanks for Him- Luke 2 v 21-24. However, the Jewish religious leaders stated that only doves bought in the Temple were acceptable as sacrifices, citing the Biblical command that all sacrifices should be of animals without defect. The price of a dove inside the Temple was about fifteen times as much as one purchased outside. These sacrifices could only be bought with the Temple coin which could only be exchanged using the coins used in everyday life by the money-changers in the Temple who exploited the Pilgrims with fees. Also, each person attending the Passover or one of the other Great Feasts had to pay the Temple tax which was around two days wages for the working man, but the fee to exchange into the Temple coin was another half a days wage!
All of this profiteering was managed by the family of Annas, who had been the High Priest and was still the power behind the throne- John 18 v 24. This was an abuse which every Jew would have known about, so when Jesus began overturning the tables He would have been roared on by the crowds around Him. Surely this man was the Messiah, the one who would make them victorious again and bring peace as David had done!
So, what caused Jesus to act as He did?
1. He was angry at the exploitation of the pilgrims.
2. He was angry at the desecration of God's holy place. Commercialisation of the sacred was violating it.
3. The stalls were in the court of the Gentiles and no non-Jew was allowed to progress beyond that point. It appears from what He quotes that Jesus was also incensed at the exclusiveness of Jewish worship: ''My house shall be called a house of prayer FOR ALL PEOPLES.''
4. He was fulfilling prophecy.