妙法蓮華經玄贊 10.6

10.6

解妨者，此品不但自生隨喜，亦教勸人，何故不名勸人之品？答：從本為名，因自隨喜方勸人故。又二俱是隨喜所攝，故合為名。

Resolving difficulties: This chapter not only concerns generating rejoicing oneself, but also teaching and exhorting others; why is it not called the chapter on exhorting others? Answer: It takes its name from the root, because it is only based on rejoicing oneself that one can exhort others. Furthermore, both are subsumed under rejoicing, and thus they are combined under this name.