Musnad Ahmad 30:3123

Surayj ibn al-Nu‘man narrated to us, Fulayh narrated to us, from Hilal, from ‘Abd al-Rahman, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, Allah, the Almighty and Majestic, says: 'I am as My servant expects Me to be, and I am with him when he remembers Me. If he remembers Me in himself, I remember him in Myself; and if he remembers Me in a gathering, I remember him in a gathering better than the gathering in which he remembers Me. If My servant draws near to Me by a span, I draw near to him by a cubit; and if he draws near to Me by a cubit, I draw near to him by an arm's length. And if he comes to Me walking, I come to him rushing. To Him belongs the favor and the grace.'"