The term “backbiting” refers to a malicious talk about someone behind their back or finding flaws in their absence. Morally speaking backbiting means talking evil about one’s religious brother in their absence whether it is about their attributes like physical appearance, character, actions, speech or anything related to them for example, their house or their dressing.
The literal meanings of innerself are existence, reality or essence. Certainly, in idiom and sentences its simple meanings are expressed unless the contrary is implied. For some men the term means soul and strength but Sufis do not take any of the aforementioned meanings into account. They take innerself as the origin of evil and centre of vice. For some attach it to soul and like man is alive so is it.
Islam is the way that leads to the Lord, Allah. Like any other way, the soul of Islam, Sufism, requires the seeker of Allah to pass different stages to become One. The very first stage is sharia then the intermediary stages are tariqa, reality (haqiqa) and gnosis (marifa) whereas the last one is Faqr (Oneness).