Fourth Yang is located in the midst of the yin and, finding itself as it does here at a time fraught with fear, it becomes the ruler of all the yin lines. As such, one here should bravely assert himself in order to bring security to all.
Wang Bi’s commentary establishes that Quake’s proper response is courageous self-assertion rather than succumbing to fear, making moral luminosity contingent on how one bears the shock.
, The Classic of Changes: A New Translation of the I Ching as Interpreted by Wang Bi, 1994thesis