Throughout the Bible, God talks to us on how we should deal with the poor. God warns us that if we willfully oppress the poor (as well as the fatherless and the widow), He will not allow us to get away with it!
God has shown me great mercy in the past. He has always provided for my needs, and has kept me safe, even during the worst storms I have ever experienced. If I strike out against the poor and needy, wouldn’t I be showing contempt to God for all the times He was merciful to me? God loves for us to show mercy, even when it is within our powers (and rights) to bring judgment and destruction.