Sahih Bukhari | Volume 9 | Hadith Number 627

Narrated by Anas
The Prophet said, "My Lord says, 'If My slave comes nearer to me for a span, I go nearer to him for a cubit; and if he comes nearer to Me for a cubit, I go nearer to him for the span of outstretched arms; and if he comes to Me walking, I go to him running.'"