A retreat is described here from the rear, and the rear is where it goes wrong. Legge's translation puts the subject at the retiring tail, calls the position perilous, and directs that no movement in any direction be made, while the commentary on the image adds that by not moving, calamity is avoided. The figure is the sky above a mountain, height withdrawing from height, and the counsel of the hexagram as a whole is a withdrawal made in good order. This line is the part of that withdrawal which has not yet begun to move and is already exposed.
Position accounts for the severity. The stroke is yielding in an odd place, incorrect by the ordinary rule, and it stands at the very bottom of the lower trigram Gen, the mountain, whose nature is to stop. Gen is two yielding lines under one firm one, so the strong stroke that gives the trigram its stillness lies two places above this one. The line has neither the strength to move well nor the elevation to be out of reach, which is exactly the condition of a rearguard.
What the text prescribes is stillness rather than speed, and the distinction carries the line. A tail that thrashes draws pursuit onto the whole body. The Great Symbolism reads the figure as the superior man holding small men at a distance by dignified gravity rather than by any show of dislike, and at this station the gravity is all there is: no ground has been put between the subject and the difficulty, and the only correct action available is to make no movement at all.