Commentary On Ezekiel Volume 1 by Jean Calvin
We must now see why the Prophet says, each animal walked onwards, or in the direction of his face. I simply interpret it in a straight course, so that they neither wandered nor declined to either the right hand or the left. For those who turn the face on one side or the other, often stumble, and thus decline from the right way: there was therefore such attention in the animals, that they always kept their object in view, and never bent from their fixed purpose. Hence we see that a fixed, and, as we say, inflexible rule in divine actions is here commended. Men often change their places, and fluctuate, and when they have any purpose, if a different thought strike them, they are carried back again, as if they had forgotten themselves. But God wishes to show that his actions are so arranged, that they have nothing in them either crooked or erroneous. For we have said that angels are represented by these living creatures; and under the image of angels the government of the whole world is signified, because it must be held, that they are, as it were, the hands of God, since he used them in obedience to his will.