Practise what you preach

परोपदेशे पाण्डित्यम्
सर्वेषां सुकरं नृणाम् ।
धर्मे स्वीयमनुष्ठानम्
कस्यचित्तु महात्मनः ॥

- हितोपदेशः

It is easy for everyone to acquire skills for preaching others. But to practise the righteous principles oneself is a quality of few that are great.

Practise what you preach.
To believe in something, and not to live it, is dishonest.