hadith
4559
۞
Imam Ali (AS) said, Keeping vigil at night in the remembrance [and worship] of Allah is the devotion of the Gnostics and the delight of the Near Ones.
الإمامُ عليٌّ (عَلَيهِ الّسَلامُ) : سَهَرُ العُيُونِ بِذِكْرِ اللّهِ خُلْصانُ الْعارِفينَ وَ حُلْوانُ الْمُقَرَّبينَ