Da Xu opens with a strong line held back before it has taken a single step. Legge's translation places its subject in a position of peril and finds advantage in stopping the advance rather than continuing it. The peril is not moral. It is structural: a yang line at the base of the lower trigram Qian, all creative force and no accumulated weight, standing beneath a mountain that has every intention of holding it down.
Correctly placed in an odd position, this line is not doing anything wrong, which is what makes its counsel worth stating. The hexagram concerns strength stored rather than strength spent, and the first thing a strong impulse encounters here is not an obstacle to be argued with but a restraint it cannot outmatch. Pressing on against the whole upper trigram Gen at this point is simply a mismatch of force, and the tradition reads the resulting danger as the natural outcome of that mismatch.
Set at the beginning of the sequence, the line establishes the terms the remaining five will work within. The second is halted, the third is put through daily practice, the fourth and fifth restrain a growing strength at its source, and only the sixth is released. All of that depends on this opening position accepting a stop it did not choose, and on recognising that a halt at the outset costs almost nothing beside one imposed later.