Answered by Shaykh Yusuf Weltch
Question
Can someone who commits major sins but is honest command good and forbid evil because he practices what he preaches?
Assume a thief telling an adulterer not to commit adultery or someone who disobeys their parents tells others to do Salah while performing Salah himself.
Is it therefore permissible for him to command good and forbid evil in this manner?
Answer
In the Name of Allah, the Most Merciful and Compassionate
Commanding to the good and forbidding the evil are obligations of the religions (if the appropriate conditions are met). Furthermore, implementing the rulings of the Sacred law is yet another obligation. Neither of these is possible without knowledge of the Sacred law, therefore, seeking knowledge is yet a third obligation. [Haddad; al-D’awa al-Tamma]
Not a Zero-Sum Game
If one seeks knowledge, yet doesn’t implement it, and still commands the good – they are fulfilling 2 out of the 3 obligations. They are then relatively better than one who seeks knowledge, doesn’t practice, and also doesn’t command the good and forbid the evil. [Ibid.]
So to answer your question, yes. Someone who is not fully implementing the Sacred law on themselves can and still should command the good (with the appropriate sincerity, knowledge, and wisdom). If full obedience to the Sacred law were a condition of commanding the good and forbidding the evil, the only ones who would be able to do it are the Prophet’s and the elite of Allah’s servants (and few they are, in comparison). [Ibid.]
Most Effective
Note that if one is fully implementing everything they are calling to, the affect of the commanding and forbidding will be exponentially greater. [Ibid.]
Hope this helps
Allah knows best
[Shaykh] Yusuf Weltch
Checked and Approved by Shaykh Faraz Rabbani