Imam Ahmad, may Allah have mercy on him, recorded that Qays bin Kathir said,
One of the people of Al-Madinah came to Abu Ad-Darda', may Allah be pleased with him, when he was in Damascus. (Abu Ad-Darda') said, `What brought you here, my brother?'
He said, `A Hadith which I heard that you narrate from the Messenger of Allah.'
He said, `Have you come for trade?'
He said, `No.'
He said, `Have you come for any other reason?'
He said, `No.'
He said, `Have you come only to seek this Hadith?'
He said, `Yes.'
He, may Allah be pleased with him said, `I heard the Messenger of Allah say: Whoever follows a path to seek knowledge, Allah will show him the way to Paradise. The angels lower their wings being pleased with the one who seeks knowledge. Whoever is in the heavens and on earth, even the fish in the sea, ask for forgiveness for the scholar. The superiority of the scholar over the worshipper is like that of the moon over all other heavenly bodies. The scholars are the heirs of the Prophets, for the Prophets did not leave behind Dinars and Dirhams, but they left behind knowledge; and whoever receives it, receives an abundance of good fortune.''
It was also reported by Abu Dawud, At-Tirmidhi and Ibn Majah.
Surah Fatir (35) - Tafsir ibn Kathir.