In Genesis 33:4, the Torah tells us about a kiss: after thirty-four years in which Jacob had fled his brother's wrath, and in which Esau had never ceased plotting to kill him, Esau has a change of heart. Seeing Jacob approach, Esau runs to him, embraces him, and kisses him.
But the word vayishakeihu, "and he kissed him," has a line of dots above it, which is the Torah's way of telling us that this was not a normal kiss. What was abnormal about this kiss? The Midrash cites two interpretations. One is that the Torah is telling us that it was not a true kiss -- Esau was really trying to kill Jacob by biting his throat. The other interpretation is that Esau kissed Jacob with all his heart -- that's what was abnormal about the kiss, since "we know that it is a cardinal law of reality that Esau hates Jacob."
Either way you look at it, the bottom line is that Esau hates Jacob. No matter what Jacob does, Esau hates him. If Jacob appeases him, gives him gifts, acts towards him like the brother he is, Esau hates him even more. But why?
Why does Esau hate Jacob? But first we should ask: Why does Esau exist at all? Why is there evil in our world? Why is there hatred and darkness? What would be wrong with a world consisting only of goodness, love and light?
Evil exists because it is so much more powerful than good. Is there a lover in the world who loves with the intensity that a hater hates? Is there a light as bright as darkness is black? Has there ever been an act of kindness unleashed with the force and vigor contained in an act of cruelty?
That is why, say the Kabbalists, G‑d created evil. Darkness exists so that it should be transformed into light, resulting in a luminance infinitely greater than light itself could ever yield. Cruelty is implanted in the heart of man so that we should tap its intensity to fuel acts of kindness infinitely more potent than kindness itself could ever produce. Evil exists to be exploited by goodness.
The soul of Esau knows this -- that he exists solely to serve his younger brother. That no matter how ferociously he resists this truth, that ferociousness itself will ultimately be Jacob's.
That's why Esau hates Jacob so much: because he knows that his hate is not his own.