Musnad Ahmad 30:3779

Rawh narrated to us, Malik narrated to us, from Abdullah ibn Abd al-Rahman ibn Ma'mar, from Abu al-Hubab, from Abu Hurairah: That the Messenger of Allah, may Allah bless him and grant him peace, said: "Indeed, Allah, the Almighty and Majestic, will say on the Day of Resurrection: 'Where are those who loved one another for the sake of My Majesty? Today I shall shade them in My shade, on a day when there is no shade but My shade.'"