Nahj al-Balāgha
Hadith 1990٥. وَقَالَ (عليه السلام): الْعِلْمُ وِرَاثَةٌ كَرِيمَةٌ وَالْآدَابُ حُلَلٌ مُجَدَّدَةٌ وَالْفِكْرُ مِرْآةٌ صَافِيَةٌ.
5. Amīr al-mu’minīn, peace be upon him, said: Knowledge is a venerable estate; good manners are new dresses; and thinking is clear mirror.