Imam Ali (AS) said, One who increases his study of knowledge [and discussion about what he has learnt] does not forget what he knows and benefits from it that which he does not know.
الإمامُ عليٌّ (عَلَيهِ الّسَلامُ) : مَنْ أكْثَرَ مُدارَسَةَ العِلْمِ لَمْ يَنْسَ ما عَلِمَ وَ اسْتَفادَ ما لَمْ يَعْلَمْ