The fourth line is the one place in Following where being followed becomes dangerous. Legge's translation shows its subject followed and obtaining adherents, says that even though he be firm and correct there will be evil, and then supplies the way out: sincerity in his course, and clear intelligence about it, leave him free from error. The sequence is deliberate. The danger is stated before the remedy, and it is not removed by being in the right.
A strong stroke stands in an even place at the base of the upper trigram Dui, incorrectly positioned by the rule and, more to the point, directly beneath the ruling fifth line. A minister who attracts a personal following in that position has created a second centre inside a structure that has only one seat, and the classical reading of the evil here is not that his conduct is bad but that his situation is ambiguous, which is a different and less curable problem.
Sincerity and clarity answer the ambiguity rather than the conduct. What makes a following beneath a ruler dangerous is that nobody can see what it is for, and that unseen purposes get supplied by whoever is watching. The remedy the line names is therefore visibility: an openly declared aim, a course that can be examined, nothing held back that would change the reading if it came out. On those terms the adherents stop being a rival centre and become simply the work being done.