Sirach 37:19

19 Some people instruct many, but they are useless to themselves.

Sirach 37:19 In-Context

17 The key to change is the heart;

18 it poses four possibilities: good and evil, life and death, and their continual master is the tongue.

19 Some people instruct many, but they are useless to themselves.

20 Some skilled speakers are hated; they will be deprived of any luxuries.

21 The Lord hasn't granted them any refinement, because they are deprived of any wisdom.