Rabbi Ahron Lopiansky
The Ox and the Donkey: An Invincible Force
The message from Yaakov to Esav is interpreted as either:
a] Appeasing; i.e. I haven't gained any of the wealth that our father promised and therefore you have nothing to be upset about;
b] Bribing; as the Ramban interpreted it, as hinting at a possible bribe to keep Esav satisfied;
c] A show of strength; i.e. "I may seem quite helpless but I've dealt with Lavan and bettered him at his game, and can do the same with you" (see Ba'al Haturim Ha'aruch.)
The Midrash Tanchuma (1) also interprets it as a show of strength, but in a more spiritual sense:
The Midrash also discusses the fact that these two tribes of Yehuda and Yosef have particular references regarding their ability to vanquish Esav.
The Midrash's interpretation that this passuk refers to some spiritual strength implies that the issue being addressed in the passuk is a spiritual struggle, i.e. Esav embodying both the force of evil inclination leading Israel astray, and simultaneously embodying the Satan who demands Israel's annihilation because of their misdeeds (as the Zohar explains at great length regarding the yom hadin. Our parsha, says the Zohar, is alluding to Esav's showing up at the yom hadin and demanding that Israel be made to suffer for their sins.)
We therefore may understand Yaakov's boast about Yosef. He is the "ox" which is a paradigm of strength, as Rashi explains regarding the metaphor which compares Yosef to an ox, "he is as powerful as an ox in conquering various kingdoms" (Devarim 33:17.)
But what is expressed by having Yehuda compare to a donkey? A donkey poses neither the beauty and grace of a horse nor the strength of an ox; the donkey is a just a plodding wretched creature. The passuk that the midrash uses about an impoverished moshiach riding on a donkey, represents an Israel at its nadir. What is there to boast about?
The answer is that the Midrash is actually revealing to us the secret of successful struggle with the forces of evil. That struggle, in order to be truly successful, requires two different, almost opposite, strengths. The first strength is the courage to proactively fight that which is bad, as Chazal tell us, "Raish Lakish said, 'a person should always use his good inclination to confront his evil inclination'" (Berachos 5a.) This requires strength and courage, best represented in the form of an "ox" proactively charging ahead with his powerful body pushing hard. A person should not spend his life guarding himself from the more base elements of his nature; rather he should proactively keep changing and developing his character.
But that alone is not enough, for no matter how hard a person tries, he will inevitably fall at various times. And each fall adds more and more "baggage", mental and emotional. He will have to struggle with the weight of his misdeeds that are dragging him down. It is human nature that even if a person fights energetically when winning; if he begins to suffer defeat, he becomes demoralized and loses his will to continue fighting or even going on at all. This is where the strength of the donkey comes into play. It is not the charging strength of an ox, rather it is the strength to bear burden on top of burden and still continue onwards.
Moshiach will eventually come riding on a donkey, for the final redeemer will be the one who can take a nation, perhaps overwhelmed by its wrongdoings over the millennia, and have it keep plodding on. The donkey may seem slow and ungainly, but it will continue onwards and eventually cross the finish line.
Yes, it is only when Yaakov had begotten the powerful charging strength embodied in Yosef Hatzaddik, along with the strength of bearing that Yehuda, the quintessential ba'al teshuva, brought to Klal Yisroel, was Yaakov assured that he will someday triumph over Esav.