He placed the cherubim
God placed the cherubim and a flaming sword that turned every way to guard the way to the tree of life, so that Adam and Eve could not eat of the tree of life. (Genesis 3:22-24)
He sits on the cherubim
The ark of God (Ark of the Covenant), which is called by the name of the LORD of hosts who sits enthroned on the cherubim. (2 Samuel 6:2)
He rode on a cherub
In my distress I called upon the Lord; to my God I called. From his temple he heard my voice, and my cry came to his ears.
Then the earth reeled and rocked; the foundations of the heavens trembled and quaked, because he was angry. Smoke went up from his nostrils, and devouring fire from his mouth; glowing coals flamed forth from him. He bowed the heavens and came down; thick darkness was under his feet. He rode on a cherub and flew; he was seen on the wings of the wind. He made darkness around him his canopy, thick clouds, a gathering of water. Out of the brightness before him coals of fire flamed forth. The Lord thundered from heaven, and the Most High uttered his voice. And he sent out arrows and scattered them; lightning, and routed them. Then the channels of the sea were seen; the foundations of the world were laid bare, at the rebuke of the Lord, at the blast of the breath of his nostrils.
The Tetramorphic Cherubs
You must solve the puzzle of a dichotomy to decipher symbolic structures like Ezekiel’s cherubs. Cosmic categories like thrones, cherubs, and wheels are as fundamental to cosmology as space, energy, and time are to materialism.
Eagle, human, bull and lion might seem random, but they perfectly describe the inner structures of this cosmology. Ezekiel was using symbolic language to describe the process of obtaining divine knowledge.
At the top, the eagle represents a spiritual or heavenly principle too abstract to be grasped without tangible expressions. At the lower end, the lion-bull duality represents the corporeal or earthly basis that provides concrete support for that principle. At the center, the human is the knower that unites the spiritual and corporeal realities.
(The Language of Creation: Cosmic Symbolism in Genesis - A Commentary by Matthieu Pageau, 2018. Pages 33-34)