Ezekiel 1:10

As for the likeness of their faces, they four had the face of a man, and the face of a lion, on the right side: and they four had the face of an ox on the left side; they four also had the face of an eagle.

They four had the face of a man - namely, in front. The human face was the primary and prominent one, and the fundamental part of the composite whole. On its right was the lion's face; on the left, the ox (called "cherub," ); at the back, from above, was the eagle's.