Imam Ghazali Rehmatullah Alaih: "(Just like other forms of religious knowledge) the knowledge of Tasawwuf is also Farz (obligatory), which means the knowledge of feelings of the Qalb (heart), like Tawakkal (being satisfied with what one has), Khashiat (being fearful of Allah) and Raza-bil-Qaza (being satisfied with the Will of Allah)." [Ta'leem Al-Muta'allimeen]
