Owing to human nature, the Torah knows it will be easier for the donor to part with his contribution to the poor if it is of an inferior grade. He will begin to realize that the poor also have to be sustained. You shall not hate your brother in your heart. We must endeavor to understand the rationale behind the Torah's admonishment against hating a fellow Jew. Hate and love are emotions that, for the most part, are natural responses.
Hatred is the product of something.
One does not hate for no apparent reason. Something motivates this hatred. Horav Gershon Liebman, zl, remarks that, indeed, jealousy fans the flames of hatred. Miriam Ha'Neviah, who risked her life to see to it that her baby brother Moshe was saved, was envious of Moshe. Indeed, it is because one recognizes his own unique characteristics and abilities that he has little tolerance for his friend's success.