These were the same creatures I had seen near the Chebar River. They controlled when and where the wheels moved--the wheels went wherever the creatures went and stopped whenever they stopped. Even when the creatures flew in the air, the wheels stayed beside them.
I heard what sounded like a voice from somewhere among the four living creatures. It said, "A quart of wheat will cost you a whole day's wages! Three quarts of barley will cost you a day's wages too. But don't ruin the olive oil or the wine."