Sufi Master Younus AlGohar's Guidelines for Novice Sufis (2)

Control your tongue. As a Sufi, you must make sure that you do not backbite. You do not slander anybody. A Sufi cannot afford to do this.

Islam has forbidden it. God even instructs against backbiting in Quran 49:12

‘Would you like to eat your dead brother’s flesh? Just as you are disgusted by the idea of eating your dead brother’s flesh, God is disgusted by backbiting’. 

The Quran mentioned Mardaat Allah - the deeds which please the Lord.

‘And one who has sold himself to please the Lord.' Quran 2:207