Abu Huraira reported: The Prophet, peace and blessings be upon him, said:


قَالَ اللَّهُ عَزَّ وَجَلَّ أَنَا عِنْدَ ظَنِّ عَبْدِي بِي وَأَنَا مَعَهُ حَيْثُ يَذْكُرُنِي وَاللَّهِ لَلَّهُ أَفْرَحُ بِتَوْبَةِ عَبْدِهِ مِنْ أَحَدِكُمْ يَجِدُ ضَالَّتَهُ بِالْفَلَاةِ وَمَنْ تَقَرَّبَ إِلَيَّ شِبْرًا تَقَرَّبْتُ إِلَيْهِ ذِرَاعًا وَمَنْ تَقَرَّبَ إِلَيَّ ذِرَاعًا تَقَرَّبْتُ إِلَيْهِ بَاعًا وَإِذَا أَقْبَلَ إِلَيَّ يَمْشِي أَقْبَلْتُ إِلَيْهِ أُهَرْوِلُ

Allah the Exalted says: I am as my servant expects me and I am with him as he remembers me. If he remembers me in himself, then I will remember him in myself. If he mentions me in a gathering, then I will mention him in a greater gathering. When he draws near to me by the span of his hand, I draw near him by the length of a cubit. When he draws near me by the length of a cubit, I draw near him by the length of a fathom. When he comes to me walking, I will come to him running.

Source: Sahih Bukhari 6970