יחזקאל י:א פירוש: רש״י

over the heads of the cherubim Over the heads of the four living beings of the Chariot. In this chapter, he switches over to calling them [all] cherubim because the face of the ox was transformed into the face of a cherub, as it is written in this chapter. Our Rabbis said (Chag. 13b): Ezekiel begged for mercy and transformed it to a cherub. He said before Him, “Master of the world, an accuser cannot become a defender.”