Charles Ellicott Commentary Job 26:10

"He hath described a boundary upon the face of the waters, Unto the confines of light and darkness." — Job 26:10 (ASV)

He hath compassed the waters with bounds. —Rather, He has described a circle upon the face of the waters, to the confines of light and darkness. The phenomenon described is that of the horizon at sea, which is a perfect circle, and which is the limit apparently of light, and beyond which is darkness, for all is invisible.