The Prophet said: "The foundation of your faith is watchfulness."
There are 3 ranks of watchfulness of people. First is the watchfulness of common people which depends on avoiding those things that are uncertain. This is outside the sphere of specific commandments given in scripture regarding what is prohibited (haram) and permitted (halal).
Ibn Siran said: "There is nothing easier for me than watchfulness: If something causes doubt in me, I leave it."
Second rank consists of those who are careful concerning anything that the heart stands back from, from anything that contrives in the breast when grasped. This is the watchfulness of the select. Prophet said: "Sin is what contrives in your breast."
"Ask your heart, even if the masters of law render an opinion for you" - Prophet
Abu Said al-Kharraz said: "Watchfulness is remaining free from even a mote's weight of wrong among creatures, so that no one can associate with you any wrong, claim of wrong or desire of wrong."
The Third rank of watchfulness consists of the gnostics (arifun) and the finders / ecstatics (wajidun). This is the watchfulness about which Abu Sulayman ad-Darani said, "Everything that distracts you from God is suspicious." The watchfulness in which God is not forgotten is the watchfulness about which Shibli was asked. Someone said to him, "What is watchfulness?" He said, "That you are scrupulous lest your heart be scattered from God Most High and Transcendent for the blink of an eye." This is the watchfulness of the select of the select.
- The Seven Stations from Abu Nasr as-Sarraj's (378/988) The Book of Flashes (Kitab al-Luma), credit Early Islamic Mysticism
There is only one virtue
...............and only one sin
....................for a soul on the path:
virtue when he is conscious of God
..................and sin when he is not.
- Abu Hashim Madani