Jami` at-Tirmidhi: Book 41, Hadith 38

Narrated Qais bin Kathir: “A man from Al-Madinah came to Abu Ad-Darda when he was in Dimashq. So he said: ‘What brings you O my nephew?’ He replied: ‘A Hadith reached me which you have narrated from the Messenger of Allah (ﷺ).’ He said: ‘You did not come for some need?’ He said: ‘No.’ He said: ‘Did you come for trade?’ He said: ‘No, I did not come except seeking this Hadith.’ So he said: ‘Indeed, I heard the Messenger of Allah (ﷺ) saying: “Whoever takes a path upon which he seeks knowledge, then Allah makes a path to Paradise easy for him. And indeed the angels lower their wings in approval to the one seeking knowledge. Indeed forgiveness is sought for the knowledgeable one by whomever is in the heavens and whomever is in the earth, even the fish in the waters. And superiority of the scholar over the worshiper is like the superiority of the moon over the rest of the celestial bodies. Indeed the scholars are the heirs of the Prophets, and the Prophets do not leave behind Dinar or Dirham. The only legacy of the scholars is knowledge, so whoever takes from it, then he has indeed taken the most able share.