Sunan Ibn Majah 3822
It was narrated from Abu Hurairah that :
the Messenger of Allah (saas) said: "Allah says, 'I am as My slave thinks I am, and I am with him when he mentions Me. If he makes mention of Me to himself, I make mention of him to Myself; and if he makes mention of Me in an assembly, I make mention of him in an assembly better than it.  And if he draws to Me a hand-span length, I draw near to him a forearm's length.  And if he comes to Me walking, I go to him in a hurry."
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَعَلِيُّ بْنُ مُحَمَّدٍ، قَالاَ حَدَّثَنَا أَبُو مُعَاوِيَةَ، عَنِ الأَعْمَشِ، عَنْ أَبِي صَالِحٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ ‏
"‏ يَقُولُ اللَّهُ سُبْحَانَهُ أَنَا عِنْدَ ظَنِّ عَبْدِي بِي وَأَنَا مَعَهُ حِينَ يَذْكُرُنِي فَإِنْ ذَكَرَنِي فِي نَفْسِهِ ذَكَرْتُهُ فِي نَفْسِي وَإِنْ ذَكَرَنِي فِي مَلإٍ ذَكَرْتُهُ فِي مَلإٍ خَيْرٍ مِنْهُمْ وَإِنِ اقْتَرَبَ إِلَىَّ شِبْرًا اقْتَرَبْتُ إِلَيْهِ ذِرَاعًا وَإِنْ أَتَانِي يَمْشِي أَتَيْتُهُ هَرْوَلَةً ‏"‏ ‏.‏