hadith
9898
۞
Imam Ali (AS) said, Knowledge about oneself is the more beneficial of the two types of knowledge.
الإمامُ عليٌّ (عَلَيهِ الّسَلامُ) : اَلمَعْرِفَةُ بِالنَّفْسِ أنْفَعُ المَعْرِفَتَيْنِ