The Messenger of Allah (salla Allahu alayhi wa sallam) said:
“Knowledge if of two types: knowledge that is in the heart, and that is the knowledge that benefits, and knowledge on the tongue, and that is God’s evidence against His creation.” (1)
1) It was narrated on the authority of al-Hasan al-Basri by Abdullah Ibn al-Mubarak in Kitab al-zuhd wa’l-raqa’iq, Ibn ‘Abd al-Barr in Jami’ bayan al-‘ilm wa fadlih, and al-Darimi in his Sunan via two different chains to al-Hasan al-Basri, all of which are correct authentic chains back to al-Hasan.
Ibn ‘Abd al-Barr added that in another chain al-Hasan al-Basri narrated it on the authority of Anas ibn Malik.
Al-Khatib al-Baghdadi narrated it from yet another chain on the authority of al-Hasan al-Basri from Jabir ibn Abdullah.
Abu Nu’aym narrated it in al-Arba’in on the authority of Qatada, on the authority of Anas ibn Malik.
Al-Hakim al-Tirmidhi likewise quoted it in Kitab Ithbat al-‘Ilal.