We brought the ox in Perek Shira, which says the Pasuk of Az Yashir as its song, and we asked why specifically this Pasuk. Chazal bring another explanation – the ox is the symbol of taking on a yoke, a burden. And since in Az Yashir, each and every member of Bnei Yisrael accepted upon themselves to be a servant of Hakadosh Baruch Hu, this is what the Navi says: אֵבוּס בְּעָלָיויָדַע שׁ וֹר קֹנֵהוּ וַחֲמוֹר – The ox knows its owner, and the donkey its master's crib. According to this, it is also understood why Pharaoh had to say, "You are free, you are released!" – because we transformed from being servants of Pharaoh to being servants of Hakadosh Baruch Hu!
In the merit of accepting servitude to Hakadosh Baruch Hu, may we merit to hear the final Shira, with the coming of the Mashiach Tzidekeinu, Amen v’Amen!
