وَ سَمِعَ عليه السلام رَجُلًا مِنَ الْحَرُورِيَّةِ يَتَهَجَّدُ وَ يَقْرَأُ فَقَالَ:
Amir al-mu'minin, peace be upon him, heard about a Kharijite who said the mid-night prayers and recited the Qur'an, then he said:
نَوْمٌ عَلَى يَقِينٍ
Sleeping in a state of firm belief
خَيْرٌ مِنْ صَلَاةٍ فِى شَكٍّ .
is better than praying in a state of doubtfulness.