As a divinatory line, nine at the fifth place of Gathering Together reads within the hexagram's overall concern with union and being collected, docile obedience leading on to satisfaction; the king approaches his temple, and firm correctness brings advantage. The line occupies a place proper to its own nature in the classical doctrine that odd places favour a firm, yang line and even places favour a yielding, yin line. It is also one of the two central lines of the hexagram, the place classical reading treats as the most balanced regardless of the line's own character. Its own text, that union in his dignified position, no error, but if there are those still not sincerely attached, firm perseverance in the right course brings the regret to disappear, is the particular fortune assigned to this one stage of the situation, not to the hexagram as a whole.
The fifth line corresponds by classical convention with the second line, and the two correspond here, since one line is yin and the other yang. Read together with the trigram it belongs to, Dui in the upper position of the figure, the line marks the ruling stage of the hexagram, the place classical reading treats as its centre of authority, one stage in the six stage movement the hexagram traces from its first line to its last.
A change at this line, from yang to its opposite, is the mechanism the tradition uses to move from one hexagram to another. Flipping the fifth line of Gathering Together turns Dui into Zhen while the other trigram, Kun, stays as it is, which yields Gathering Together's changing partner, Enthusiasm (King Wen 16), the hexagram this line is recorded as transforming into.