Musnad Ahmad 28:301

Hajjaj ibn Muhammad narrated to us, Ibn Lahi'ah narrated to us, from Rashid ibn Yahya—[Abdullah ibn Ahmad said]: My father said: Hassan al-Ashyab said: Rashid Abu Yahya al-Mu'afiri—that he heard Abu Abd al-Rahman al-Hubuli, from Ibn 'Amr, who said: I said: "O Messenger of Allah, what is the spoils of the gatherings of dhikr (remembrance)?" He said: "The spoils of the gatherings of dhikr is Paradise."