The order the Torah gives us when commanding us which animals are kosher for sacrifice are: ox, sheep, and goat. Why does Hashem give over the ox first? Why not the sheep or goat? The reason for this is that Hashem wanted to teach that He did not blame Bnai Israel for the sin of the golden calf. Rather, the airev rav- converted Egyptians- were the ones to blame. They created the golden calf and proclaimed to Bnai Israel that ‘this is your god!’ Furthermore, in order to avoid the nations of the world sneering at us saying, ‘You made a golden calf!’ Hashem put an ox at the head of the list of korbanot in order to counteract those slanderous statements for people to see that Jews sacrifice oxen, they do not serve them as gods.