Do not withhold good from one to whom it is due, when it is in your power to do it (Proverbs 3:27).
Rabbi Samson Raphael Hirsch points out that the word that is commonly used for charity, tzedakah, really does not mean giving alms. It is derived from the word tzedek, meaning "justice." When people give tzedakah, they may feel that they are making a sacrifice by giving to another person from their own money. They may even resent the recipient of tzedakah for taking away from their assets. The Torah tells us that this attitude is wrong: "Do not give with a bad heart" (Deuteronomy 15:10), and the reason is in the verse cited above. What we give the poor is rightfully theirs, and the person of means is really only the trustee of the poor's property.
"Do not rob from the poor" (Proverbs 22:22). What do poor people own that we can rob from them? This verse refers to withholding tzedakah, because when people do so, they keep for themselves what rightfully belongs to the poor.
People who receive tzedakah should not feel humiliated, and people who give tzedakah should not feel magnanimous. It is simply an act of tzedek, of justly distributing what rightfully belongs to each person.