"Know that tasawwuf is two things: Truthfulness with Allah Almighty and good conduct with people. Anyone who practices these two things is a Sufi. Truthfulness with Allah is that the servant puts an end to his ego's shares in the divine command. Good conduct with people is to not prefer one's demands over theirs as long as their demands are within the parameters of the Law. Whoever approves of the contravention of the Law or contravenes it can never be a Sufi, and if he claims he is, he is lying."
al-Baghdadi (d. 429)