How we treat the poor says a great deal about our heart. There is one thing God is very clear about throughout the Word of God - and that is that He desires for us to care for the poor in our society. One thing I need to differentiate before I continue is that God also makes a clear distinction between the poor and the lazy. Too often we view the poor as anyone who does not have enough - whereas God describes them as those who do not have enough, but who are that way not because they refuse to work. By saying this I am not saying that everyone who is poor is unwilling to work - but I am saying that among those who do not have enough are far too many who are that way because either they won't work - or because their lifestyle choices (i.e. alcohol, drugs, laziness) is what is the cause of their need. That being said, I want to turn to this proverb and make a few comments.
The one who oppresses the poor to make more for himself is odious to God. The word "more" here is actually the word for having much. This person is abusing the poor not because he wants to make a living - but because he wants to be wealthy. His desire to have much drives him to not see people - all he sees is money. The word "oppress" has the idea of extorting money from someone. It also is used to speak of those who cheat their workers out of their wages. There is an acceptable way to earn a large amount of money in a business, but to do so on the backs of workers who are not paid properly is not the way to do this. God will not bless such a man.
The second warning here is for those who give to the rich. These people shut their hearts to the poor - but instead give to a rich man to curry favor with him. They do so as little more than a sycophant who is wanting by his gifts to have the rich man give him something in the end. The Scriptures say that such a practice will only come to poverty in the end. There may be a temporary return for such a man's wicked investment, but in the end such practices only last as long as the gifts keep coming. Let someone else offer a larger or more impressive gift and the rich man will turn to him, forgetting the poor schlub who gave him a lesser gift last year.
Our money belongs to God - and He desires that we use it wisely. This means that we do business honestly and wisely. Giving gifts to customers is not ungodly when the gifts are given with a true sense of gratefulness for their patronage. Being wise with wages so that a business continues to make a profit is not ungodly either. What the Lord is seeking to get across to us here is that when we do business and make a bigger bottom line our god - we are going to wind up serving money rather than God. When God blesses our bottom line, He wants us to always remember the poor. To forget them and see the rich as the only ones who can continue to bless us is to ultimately forget God - Who is the ultimate One to honor and please for future prosperity and blessing.