In a world where money speaks loudly it is important to have those who are advocates for the poor. The wicked know of no such concern for this as they see the poor as a perfect target for their abuse of power. But God makes it clear that the righteous are very concerned for the poor.
The literal translation of the proverb begins with the statement, "The righteous knows the cause of the poor." This assumes that there is a cause for which the poor need help. The word used here to describe the rights of the poor is a legal word. It was used in the world of the courts and in lawsuits. What we have then is a situation in which the legal system and the courts are not working the way they should toward the poor. Thus they need for someone to be concerned and to know their plight.
This is a situation that unfortunately has existed all through history - and even more unfortunately - exists today. I watched in disgust years ago when a man who had committed a heinous murder had his sentence reduced twice because his family had the money necessary to get his case reviewed again and again. The poor know nothing of these kinds of rights. They don't have the money to afford the high priced lawyers who can use the system both for justice and injustice. The poor pretty much face the system with justice alone. Thus we see the poor going to jail - while the wealthy and influential can work the system to avoid it.
Our proverb tells us that the righteous is concerned about these things. They see the injustice and it bothers them. They want to see justice blind to money and blind to political influence. When that is not the case the righteous will fight for the cause of the poor.
The wicked don't have any kind of concern here. In fact the proverb tells us that they don't even understand concern. Their worldview has them as most important. Thus, if a poor person is convicted of a crime they did not commit - or a lawsuit is turned against the poor - the wicked don't understand why anyone is upset. In the end the wicked got what they wanted - so why all the fuss? They just go on their way unscathed and unbothered by the legal problems of the poor.
The reason this is important is because such things reveal the major differences between the righteous and the wicked. The wicked cares only about himself. He cannot see past his own desires and wants to concern himself with anyone other than himself. The righteous are concerned because they are selfless and want God's justice to prevail in all aspects of life. In the end - we see very clearly the contrast between the wicked and the righteous. But in the most important sense - what we see is a godly selfless lifestyle and that of a selfish wicked person. Knowing this we should do all we can to support the rightes of the poor. To do otherwise would be walking in the very ungodliness that we seek to avoid.