Charles Ellicott Commentary Ezekiel 1:17

"When they went, they went in their four directions: they turned not when they went." — Ezekiel 1:17 (ASV)

Upon their four sides—that is, forwards or backwards upon the one wheel, and to the right or the left upon the other. Four directions are considered throughout the vision as representing all directions, just as elsewhere the four winds represent all winds, and the four corners of the earth the whole earth.