Musnad Abu Ya'la al-Mawsili 155:349

Abu Kuraib narrated to us, Mu'awiyah bin Hisham narrated to us, from Hamzah al-Zayyat, from 'Adi bin Thabit, from Abu Hazim, from Abu Hurairah, who said: The Messenger of Allah (ﷺ) said: Allah says: "Remember Me within yourself, and I will remember you within Myself. And remember Me in a gathering of people, and I will remember you in a gathering—meaning—better than them."