Legge's translation of the fourth line reads that the fourth six, divided, shows its subject possessed of sincerity, so that the danger of bloodshed is averted and his ground for apprehension dismissed, with no mistake resulting. The commentary adds that because he is possessed of sincerity and his apprehension is dismissed, the lines above agree in aim with him.
This is the only yielding line in the entire hexagram, and it is the line that gives Small Taming its name and its whole meaning, a single small, yin force positioned to restrain the much greater strength of the five yang lines that surround it. Sitting at the base of Xun, the upper trigram of Wind, in the fourth place, it occupies the position closest to the ruler at the fifth line and carries real exposure, the kind of position where conflict could easily follow from so slight a force attempting to check so much strength. Sincerity, rather than power, is what lets it succeed.
Legge's commentary is explicit that this line's safety comes from the other lines agreeing with its aim rather than resisting it, which is the entire mechanism by which something small can restrain something great without breaking under the attempt.