Yaakov Avinu: I have MBY & MBD to Fight You, Eisav

Bereishit 32:6:

וַיְהִי-לִי שׁוֹר וַחֲמוֹר, צֹאן וְעֶבֶד וְשִׁפְחָה; וָאֶשְׁלְחָה לְהַגִּיד לַאדֹנִי, לִמְצֹא-חֵן בְּעֵינֶיךָ

And I have oxen, and asses and flocks, and men-servants and maid-servants; and I have sent to tell my lord, that I may find favour in thy sight.'

Bereishit Rabba 75:6:

רבנן אמרי שור זה משוח מלחמה שנאמר (דברים לג) בכור שורו הדר לו חמור זה מלך המשיח שנאמר (זכריה ט) עני ורוכב על חמור וגו'

The midrash tells us that Yaakov Avinu basically told Eisav that I have Mashiah ben Yosef and Mashiah ben David, so don't mess with me.

The Nezer Hakodesh explains why they are given the names of ox and donkey. He quotes the Zohar who says in many places that ox corresponds to the left, while the donkey corresponds to the right. However, the ox and donkey on the side of evil correspond to Eisav and Yishmael respectively. When Eisav married Mahalat bat Yishmael, he combined the forces of evil to make one powerful force against Yaakov. (This is why the Torah forbids us to plow with an ox and donkey together - corresponding to the evil forces of the left and right, who, if combined, will destroy the world.) To this, Yaakov Avinu countered by saying ויהי לי שור וחמור - I have the power of the ox and donkey on the side of good [i.e., MBY and MBD] to counteract the ox and donkey on the side of evil [i.e. Eisav and Yishmael]. Proof that it refers to future times is the fact that it says ויהי לי שור וחמור instead of יש לי שור וחמור. This signifies future events similar to ויהי לי לישועה.