Kitab Al-Dhikr hadith Sahih Muslim

The Book Pertaining to the Remembrance of Allah, Supplication, Repentance and Seeking Forgiveness
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying that Allah, the Exalted and Glorious, thus stated: I am near to the thought of My servant as he thinks about Me, and I am with him as he remembers Me. And if he remembers Me in his heart, I also remember him in My Heart, and if he remembers Me in assembly I remember him in assembly, better than his (remembrance), and if he draws near Me by the span of a palm, I draw near him by the cubit, and if he draws near Me by the cubit I draw near him by the space (covered by) two hands. And if he walks towards Me, I rush towards him.