Adam Clarke on Ezekiel 1:20

The spirit of the living creature was in the wheels - That is, the wheels were instinct with a vital spirit; the wheels were alive, they also were animals, or endued with animal life, as the creatures were that stood upon them. Here then is the chariot of Jehovah. There are four wheels, on each of which one of the compound animals stands; the four compound animals form the body of the chariot, their wings spread horizontally above, forming the canopy or covering of this chariot; on the top of which, or upon the extended wings of the four living creatures, was the throne, on which was the appearance of a man, Eze 1:26.