Al-Rabia’ reported: Al-Shafi’i, may Allah be pleased with him, said, “Knowledge is not merely what is memorized. Knowledge is what benefits.”
Source: al-Madkhal ilá al-Sunan al-Kubrá 400
عن الربيع قال الشافعي رَضِيَ اللَّهُ عَنْهُ لَيْسَ الْعِلْمَ مَا حُفِظَ الْعِلْمَ مَا نَفَعَ
400 المدخل إلى السنن الكبرى للبيهقي