This paragraph is the continuing discussion about how to become a successful king, and what are the qualifications of effective leaders. A leader must have a perfect will in order to control the movements of the heart. Regulating the heart movement can achieve the state of free from defects.
When Confucius emphasizes that the perfect will depends on the knowledge, he affirms that the knowledge must from scrutinizing the nature of things. This means that knowledge is not obtained studies of books but from the field practice. It roughly meas practice makes perfect.
As elaborated by Xavier Séguin at Eden Saga, these valuable advices reflect a perspective radically different from ours. While the western leaders seek to reform first the laws and behaviors of the people, according to Confucius, leaders must first correct themselves before claiming to lead.