One wheel upon the earth by the living creatures.
No stability in the world
The four living creatures denoted the four parts of the world, and their agencies in them and by them: now are presented the wheels; every living creature had a wheel by it: and this strongly implies that there are wheelings, turnings, and changes in all parts; yea, the very same that are in one part are at one time or other in another part. The wheels are alike. Are wars, plagues, famine in one country? they are, or will be, in another. Do men die here? so in all parts. Are men unfaithful now? so they were of old. Are there unseasonable times here? such are abroad. Are things carried by violence, oppression, injustice here? so they are elsewhere. Are there designs, plots upon our kingdom and Church? so there are upon others. Whatever befalls one state, befalls another, internally and externally. The wheels are the same, and move alike, though sometimes backward in one part of the world and forward in another; there is no stability anywhere, but all things are changing. In vain, then, do men travel the world to find certainty and content in it; in vain do we go up and down, here and there, thinking to find settledness, and something satisfactory. The world is like itself everywhere; go east or west, and there is nothing but a wheel, and a wheel running. We must not look for stability, content, certainty, among the wheels, but above them: now it is not time to look about and abroad, but to look above the world and the wheels of it. If we have tribulation in the world, we may have peace in Christ. (W. Greenhill, M. A.)
Symbols of Divine Providence
The sum of this celestial vision is that the Divine Providence doth rule in the world, and is exercised in all parts thereof, and not only in heaven, or in the temple, or in Jewry, as the Jews then thought. As for the changes in the world, which are here compared to wheels, they befall not by haphazard, but are effected by God, though all things may seem to run upon wheels, and to fall out as it fortuneth. At the day of judgment, at utmost, men shall see a harmony in this discord of things, and Providence shall then he unriddled. Meanwhile, God oft wrappeth Himself in a cloud, and will not he seen till afterwards. All God’s dealings be sure will appear beautiful in their season, though for the present we see not the contiguity and linking together of one thing with another. (J. Trapp.)