Shaqiq al-Balkhi (Rahmatullah alaihe) said that one of the knowers of Allah said, "Know that purity of state is only attained by the purity of one's realisation of four matters:
1. Knowing the Lord (Mighty and Exalted),
2. Knowing the lower self (nafs),
3. Knowing death,
4. Knowing that which comes after death of promises and warnings.
This is because the one who knows his Lord (Most High) fulfils His rights. Whoever knows his lower self (nafs) opposes it. Whoever knows death prepares for its coming. Whoever witnesses the promise of Allah (Most High) obeys His commands. And whoever witnesses His warnings avoids His prohibitions.
These matters are governed by three things:
1. Loyalty (wafa'),
2. Propriety (adab),
3. Dignified behaviour (muru'a).
As for loyalty, it is to make one's sole concern Allah's Solitariness (fardaniyya), to remain firm upon beholding His Oneness (wahdaniyya), and to find intimacy in the light of His Firstness (awwaliyya).
As for propriety, it is to guard one's movements and thoughts, to preserve one's moments, and to leave the interdicted.
As for dignified behaviour, it is to remain steadfast upon remembrance (Zikr) with purity, in word, deed, and intent; to protect oneself from prohibited and doubtful matters of the outward and inward; to hold fast to proper manners to be mindful of what is coming; and to make up anything missed, whether minor or major.
Whoever has all these traits will find the sweetness of union; will have avoided the pain of separation; and their heart will be ablaze with the fires of passion." (al-Wasiti, Majma` al-Ahbab Mukhtasar Hilyat al-Awliya', 3.530)