How surprised the disciples must have been. This was a side of their beloved master that they had never seen before. Then they remembered that it was written...The zeal of thine house hath eaten me up. Jesus couldn't just stand by and do nothing as the temple of God was used in such a way. This was a place of worship. A place to meet with God, not a place to make a living.
We should feel the same way today about the churches we attend. They too are places where we gather and worship God. That is exactly what they should be. Places of worship, not places of worldly business. If it wasn't right in Jesus day, it is not right today either.
The bible says in Hebrews 10:25...Not forsake the assembling of ourselves together, as the manner of some is, but exhorting one another: and so much the more, as ye see the day approaching (KJV) When we come together in a church is should not be just out of tradition or because it is just a form. It should be to worship God and help build up and encourage each other.