Musnad Ahmad 30:2228

'Affan narrated to us, he said: 'Abd al-Wahid narrated to us, he said: Sulayman al-A'mash narrated to us, he said: Abu Salih narrated to us, he said: I heard Abu Hurayrah saying: The Messenger of Allah (may Allah bless him and grant him peace) said: "Allah, the Mighty 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 it. And whoever draws near to Me by a span, I draw near to him by a cubit; and whoever draws near to Me by a cubit, I draw near to him by an arm's length; and whoever comes to Me walking, I come to him at a run.'"