Musnad Ahmad 30:2151

'Affan narrated to us, he said: Abu 'Awanah narrated to us, Sulayman al-A'mash narrated to us, from Abu Salih, from Abu Hurayrah, from the Prophet, peace and blessings of Allah be upon him, who said: "There is no group of people who gather in a house from the houses of Allah, the Almighty and Majestic, reading and learning the Book of Allah, the Almighty and Majestic, and studying it among themselves, except that the angels surround them, mercy covers them, and Allah mentions them among those who are with Him. And there is no man who travels a path seeking knowledge therein, except that Allah makes easy for him by it — or makes easy by it — a path to Paradise. And whoever is slowed down by his deeds, his lineage will not speed him up."