Legge's translation of the fifth line invokes a specific precedent, King Di Yi's own rule concerning the marriage of his younger sister, and states that by such a course there is happiness and, in the fuller tradition the line belongs to, great good fortune. The reference is to a known historical arrangement in which royal rank did not demand a match to another equally ranked house, but allowed marriage guided by something other than pride of position.
Six in the fifth place holds the central, ruling place of Kun, the upper trigram, the honored seat from which the hexagram's receptive virtue is ultimately exercised, and it is a yielding line in an odd, normally yang preferred position, which commentary reads as humility genuinely occupying authority rather than merely being granted it. The marriage precedent fits this placement precisely, a ruler's own household choosing a match on terms of suitability and blessing rather than rank alone.
Set within Peace's wider movement, the fifth line shows the hexagram's harmony reaching its most intimate register, the sovereign's own family conducting itself by the same humility the fourth line's light descent already modeled. Legge's citation of a named precedent, rather than a general image, marks this line as resting on remembered example rather than invented figure.